GTA
Airguns by Make and Model => Artemis/SPA Airguns => Topic started by: Thane on February 29, 2020, 01:29:12 AM
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PP750 in .177 showed up today and so far it's a very nice build, scales are wood. Struts better than expected, lever a bit rough and already smoothing out. Fit and finish is well beyond the price paid.
No cleaning, No polish, No adjustments - 1st string made 36 shots within 2.5% spread 9.2FPE 40 shots under 4%. You can see it come off the regulator at shot 38, fill was 250 bar, no creep notice, but longest pause was 15 minutes so jury is still out on creep. That is a sweet string and with no effort.
Magazine has sharp corners, takes some finesse to slot in. Good news is it is very deep, bad news only 9 rounds.
Trigger pull is stiff, but easily adjusted by cranking down a trigger grub screw to move it near tangency of sear bar, making a "2 stage" effect. Removing the right scale and metal handle cover reveals the very simple trigger and sear bar, cutting down the spring reduced trigger pull force. It now travels smoothly falls into a definite stop and on further pressure breaks consistently.
I just ran the hammer spring from max to min and it made a 50 fps difference. Needs a stronger spring or spacer...
Marked regulator for factory set. Any guesses on CW or CCW for increase in pressure set point??
Barrel shroud has 3 fairly effective aluminum baffles and is treaded over the breech thimble. 8" barrel is threaded into same breech thimble, a great improvement over the PP700 rotating barrel issue. The thimble has 2x 3mm transfer ports 180° opposed, served by a channel. Have to wonder if lining up a the transfer port to the thimble port will reduce resistance? Pressing a pellet through is smooth with minor choke. Crown has SPA's signature rustic appearance with some bonus scoring on the lands, a spin on the lath is in order.
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Awesome . I can’t wait to get my grubby hands on one. The trigger assembly sure looks like a simple affair . I hope it’s better than it looks. It actually reminds me of the Evanix which is actually pretty decent
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Could be awhile before we see any more in the US. :'(
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Very good, thanks for reporting back so quickly.
Marked regulator for factory set. Any guesses on CW or CCW for increase in pressure set point??
That looks like the type which moves the valve seat to change the setpoint so back out the brass screw to increase the setpoint or drive it in to reduce the setpoint.
Crown has SPA's signature rustic appearance with some bonus scoring on the lands, a spin on the lath is in order.
What a shame they continue to ruin otherwise good barrels. Both of my long-barreled SPA guns (CR600W/Plinkster and CP2/Chaser) had the rifling damage but neither of my short barrels (CP1 and PP700S-A) had it. All 4 had crowns that appeared to be done with a dull drill bit running in reverse.
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Is the regulator externally adjustable, or do you have to disassemble the gun? Kinda hard to tell from the pictures... Also, who did you order from? Hopefully, if they got theirs, Wes will be getting his shipment soon...
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Curious to know if the regulator can be removed and
.........what MAX power can be achieved.
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Very good, thanks for reporting back so quickly.
That looks like the type which moves the valve seat to change the setpoint so back out the brass screw to increase the setpoint or drive it in to reduce the setpoint.
Backed out the set screw CCW 1 turn appears to have raised the set point, but raised fps very little even with stiffer spring. I suspect the transfer port is choking it, not certain strategy to open it up.
What a shame they continue to ruin otherwise good barrels. Both of my long-barreled SPA guns (CR600W/Plinkster and CP2/Chaser) had the rifling damage but neither of my short barrels (CP1 and PP700S-A) had it. All 4 had crowns that appeared to be done with a dull drill bit running in reverse.
It would be better if SPA just de-burred it with a die grinder ball than smearing the lands. I turned off 3./16" then recrowned both endes with brass screw and polish.
Is the regulator externally adjustable, or do you have to disassemble the gun? Kinda hard to tell from the pictures... Also, who did you order from? Hopefully, if they got theirs, Wes will be getting his shipment soon...
No on external adjustment. De-gas, unscrew air tube off regulator assembly and there it is very smooth operating. I like it better than the PP700 while external is difficult to operate. Ordered from Mundilar Airguns, Portugal. Arrived 3 days after placed order, shipping is steep.
Curious to know if the regulator can be removed and
.........what MAX power can be achieved.
Reg appears to be removable, but I have not disassembled that far... So far peak power with heavy spring and 1 CCW on the reg peaked at 10.3 FPE, there is a lot of exploring left and certainly not the MAX, that will take a while and more than just my efforts.
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Handle assembly drops off with 2 screws gives access to hammer, hammer spring and setting screw, sear, trigger spring (sear is captive). Handle casting crosses the back of the hammer setting screw, making it captive.
Hammer is bored out and completely symmetrical. Spring is 9mm x 62mm with a 1.12mm wire dia.
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Is the regulator externally adjustable, or do you have to disassemble the gun? Kinda hard to tell from the pictures... Also, who did you order from? Hopefully, if they got theirs, Wes will be getting his shipment soon...
No on external adjustment. De-gas, unscrew air tube off regulator assembly and there it is very smooth operating. I like it better than the PP700 while external is difficult to operate. Ordered from Mundilar Airguns, Portugal. Arrived 3 days after placed order, shipping is steep.
Thank you! Is degassing it easy? Is there a screw or plug to release pressure or do you have to loosen the gauge?
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FYI, regarding the regulator adjustment not having much effect on velocity, I just wanted to share a few thoughts. You mentioned trying a heavier hammer spring…I assume there was enough adjustment to comfortably find the velocity plateau. In other words, adding ever more preload does not cause the velocity to increase.
I agree that opening up the porting would very likely yield substantial gains (I don’t know where the restrictions are for this particular model but I’m speaking generally). Though even if the porting is anemic, there should still be an increase in velocity proportional with the higher pressure. One question is, how much did the setpoint increase for one turn of the adjustment screw? We don’t know but I would expect it to be a meaningful amount given the limited travel of most Belleville stacks relative to any reasonable thread pitch the adjustment screw might have. Then the next question is, why wasn’t the velocity change very meaningful? Well it may be because the regulator is new and hasn’t settled in yet. The valve seat (the regulator’s valve seat, not the firing valve) will generally need to be cycled a few hundred times before the sealing surfaces will wear in and conform to each other enough to seal reliably and consistently. Until then, it’s likely to be inconsistent and creep, perhaps to the point of making it difficult to distinguish a meaningful difference after changing the setpoint. All that’s to say it would probably be a good idea to put some pellets through it to break it in and then re-evaluate the setpoint adjustment.
By the way, a “few hundred times” may be significantly more or less depending on the materials, surface quality of the parts, and their geometry. A lot of times I’ll go ahead and smooth the mating surfaces to get rid of machining marks left over from manufacturing. That will often cure a stubborn creeper that seems to never break in properly.
Another assumption is that there was some adjustment range available in the first place…that the Bellevilles didn’t start out with a condition that is nearly squeezing them flat. I think that’s a reasonable assumption but I wanted to mention it just in case. I do recall reading about some SPA regulators whose washers were stacked incorrectly from the factory. To know how they’re supposed to be arranged, you’d need either an assembly diagram or to compare notes with another owner who has successfully dialed up the regulator.
Lastly, be mindful of anything in the air path that may have become partially blocked on reassembly. The common causes are the valve’s exhaust port getting slightly out of concentricity with the transfer port/receiver port, or a transfer port seal getting crushed/deformed or not sealing well, or the barrel port getting out of alignment with the upstream ports. Also, a barrel O-ring or a breech O-ring can sometimes get a slight nick that puts some of the air to waste. Not so much that it’s completely blown but enough that a small portion of the air gets diverted away from behind the pellet where it belongs.
Well this ended up being longer than I intended but hopefully it’s some food for thought and you get to the bottom of it soon.
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Excellent information and all assistance is greatly appreciated. I hope as many as interested add to this thread.
Still trying to find the set point, adjustments are making no velocity changes. Either I have flattened the bellevilles or I am way out of range or it's leaking or breaking in...? So I am doing quarter turns till a velocity change occurs, if not the bellevilles get swapped?
The hefty valve spring partially obstructs the 3mm port serving from the regulator to the valve seat. I have opened the 3mm port up to center of valve spring. Most of the transfer port path is 3mm and the plenum has a very small volume. Brass tapered poppet with brass seat. The valves port is aligned with a slot and is pinned, it is nice and not going anywhere.
The degassing is by pressure gauge only, so that oring is getting a work out.
Regulator is a separate assembly, but not removable and it seals the air tube.
So far very impressed with the engineering and build quality with few exceptions.
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Managed to find a decent set point for the regulator, appears to be about 130 bar. With the hammer polish, heavier spring, some port clearancing and alignment I picked up over 2 FPE for the same 36 shots (was 9.2 now 11.3 a 23% increase!). However the first 17 shots velocity 3% ES, next 8 shots at 7% ES then finishes 11 shots at 1.6% ES- jumps around in the middle!
Jason's advice to check the sealing surfaces in the reg is what I'm up to next. Then some break in, maybe an LDC adapter...
Did some 5 shot groups at 25 yards it likes the HN Terminators, HN FFT 8.6gr, HN Sniper Magnum 14.9gr, JSB 8.44gr, JSB RS 7.3, JSB Heavy 10.3gr. All sub 1/2" at 25 yards. So not pellet picky. The RWS wadcutters always supprise me, 4 in the same hole and then 1 shot half inch away.
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This is what I was really hoping for- I can live with less widely adjustable power on tap (for a max) in return for 2 things: maintaining the SPA barrel's non-pickiness (albeit with a recrowning, grrrrr) and a regulated repeater. You mentioned the baffles actually work so hooray for that, too. I love single-shots but this pop-gun scratches several itches my PP700 can't quite touch.
Thane- I appreciate the teardown and build-up. Hopefully the regulator really settles in as you push more lead down the barrel, but even a somewhat wider extreme spread is something I can live with if I get accuracy.
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Peter I have enjoyed your PP700 plinking sessions, some surgical work. Twisting the PP700 block open and closed, setting the thumb hammer, gives it a unique shot cycle character with minimum hammer force required, very zen. The PP750 lever really picks up the pace, but changes the hand feel to a more common PCP hammer charging cycle complete with magazine fiddling, a different beast.
Tore down the regulator for a look-see and polish. The brass set screw is bored on center with a fine orifice and conical tip that seals against a captive plastic plug on the end of the piston. Polished the orifice tip flat, removing some mill marks. Found a silicon bead (used to make metal filter matrix) trapped in the 12 substantial 1/2" bellevilles stacked )))((()))(((, could account for jumping velocities. Trued the belleville face edges with 800 then 1500 oxide paper on a sanding board. Polishing compound with a felt tip dremmel to the interior bores the piston rides on, they are mirrors now. Inspected orings for nicks, all good. Back together for a testing....
... and the brass poppet fails! >:( Shaft pressed right through, breaking the back of the poppet.
The brass poppet is drilled for the hardened steel shaft making the brass very thin walled, eventually cracking under increased hammer force.
Time for some PEEK poppet turning, which was going to happen anyway :D. I was hoping to check the reg job by itself, not to be.
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Turned a PEEK poppet on the lathe, kept angle more shallow than brass seat to let the brass edge press into the PEEK for a more positive seal (held 250 bar overnight).
With the regulator cleaned out and polished it the velocity swings calmed right down and pulled a couple of three-peats ;D, 27 shots with 1.5% ES and 11.4 FPE. (full disclosure-weight sorted pellets).
So it's up 24% in power over the un-molested factory condition and shaved 1% off the ES, heading in the right direction!
Scoped with a UTG Bugbuster 3-12x32mm Side Objective, feather weight and adjustable to 3 yards. Scope height is 1.66" may be able to lower another 5 mm to bring my near zero in a meter or so.
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Making great strides in short fashion! Making me wish I had gotten one. I've cut myself off from any near future airgun purchases, however. My latest one, I actually got because the news and info of this one's release (to any market) was quite delayed.
It looks liek a real winner, though :D
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So, do you think there's a chance to get her to 20 FPE ?
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So, do you think there's a chance to get her to 20 FPE ?
At .177 with an 8" barrel it's going to take some opening up, lose the regulator, increase hammer mass...?
I am going to pull the regulator stack and adjustment screw to shoot an unregulated string to see if it's ports slowing it down. Could also be small plenum volume, light hammer... I doubt the stock spring/hammer could open the valve @ 250 BAR.
Looking forward to others jumping in, lots of talent here.
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Did some more shooting this weekend and this happened.
Lever is cast and thins to maintain a flush profile. I noticed it starting to bend right at the narrowing, went easy on it, but its was too late. :P
Really did not want another thin one which would be next to impossible to get right now, so I cut off some superior stainless steel bar and machined a replacement, doubling the section and closed some tolerance gaps=no slop.
Also took the opportunity to remove the sharp edges and make a finger friendly concave shape with narrow edge at front for easy finger tip pull. While I wish I didn't have to fab the lever up, it has turned out to be decent upgrade.
Take warning, there is going to be some tears shed on this part's performance, or maybe mine is just the exception...?
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I was going to buy one. But after looking at your photos and seeing your problems I think I will pass this one up.
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Decided to open up the air path:
Regulator to plenum <3mm to 5mm
Valve is 5.9 mm with 2.8 mm poppet shaft
Valve port 3mm to 4.5 mm
Transfer port 3mm to 4mm
Barrel Port 3mm to 3.5mm (filled channel with epoxy, single aligned port tapers from 4.5 to 3.5)
Also increased plenum diameter by 1mm (20% increase in a very tiny plenum).
Noticed hammer was trapping volume of air against valve face (suction when removed), slotted hammer. Also notice off center valve stem.
Netted a 10.5% increase in power (37% power increase over best stock string).
With JSB Heavy 10.3 gr it makes a flat 23 shot string at 13.6 FPE.
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I was going to buy one. But after looking at your photos and seeing your problems I think I will pass this one up.
To be fair I am pushing this airgun well beyond most, but certainly not as much as some of you ;).
PP750 is not intended to be a hand cannon and comes with a very respectable tune in 700FPS 9-10 FPE a very decent pistol speed making it a 30 yard specialist.
I am tinkering for fun, testing limits by exceeding them, then fixing it.
I can't wait for others to jump in, hopefully adding to this thread whatever mods they work up.
That's where the fun is for me, and occasionally shooting... :P
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Arts n crafts day for the PP750.
Found a guy on Etsy doing some interesting knife scales with exotic woods, multi-colored resins, aluminum hex cell...
Shaped a set of his blanks to beef up the thin factory handle, thumb ledge and bling factor.
Added a red LED flashlight for some night time visitors...
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Those look great.
Between the power level you've achieved and the overall build/tune, you've got yourself a sharp-looking compact carbine for close-in vermin/pesting. I love it!
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Agree...lookin really good!
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Thanks!
It is a fun gun to shoot and tinker with, plenty of room for modifications. Wes has to be itching to ship these, and I look forward to getting some company.
There is going to be an onslaught of modifying, it is just so easy to break down, adjust and re-assembly.
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So, do you think there's a chance to get her to 20 FPE ?
At .177 with an 8" barrel it's going to take some opening up, lose the regulator, increase hammer mass...?
I am going to pull the regulator stack and adjustment screw to shoot an unregulated string to see if it's ports slowing it down. Could also be small plenum volume, light hammer... I doubt the stock spring/hammer could open the valve @ 250 BAR.
Looking forward to others jumping in, lots of talent here.
Did you ever pull the reg stack and try it unregulated... Dying to know how that would perform...
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I did some testing with the reg stack removed. Difficult to seal air tube, takes a large/thin oring to hold air at pressure which kept pressing it out like taffy. I could only hold 2400 psi and made some 16FPE shots, only 2 FPE better than highest tune with regulator.
Next step would be to turn a channel to retain larger oring to make full pressure, increase hammer mass as it was struggling to crack the PEEK valve at 2400 PSI, increase spring force.
Plenty of room for exploring...
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Arts n crafts day for the PP750.
Found a guy on Etsy doing some interesting knife scales with exotic woods, multi-colored resins, aluminum hex cell...
Shaped a set of his blanks to beef up the thin factory handle, thumb ledge and bling factor.
Added a red LED flashlight for some night time visitors...
It would be nice to know how you add the LDC to the shroud/barrel.
Thank you
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It would be nice to know how you add the LDC to the shroud/barrel.
Thank you
I turned an adapter from aluminum on a lathe months ago.
Donny FL now has PP750 adaptors available:
https://donnyfl.com/collections/adapters/products/pp750-1-2-x-20-adapter-a63 (https://donnyfl.com/collections/adapters/products/pp750-1-2-x-20-adapter-a63)
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Don't have one yet, but I think all it is is a 1/2-20 threaded tube. Any adapter for an Umarex Gauntlet should work. Thats what I bought. Can't wait for a pistol to attach it to.
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Scoped with a UTG Bugbuster 3-12x32mm Side Objective, feather weight and adjustable to 3 yards. Scope height is 1.66" may be able to lower another 5 mm to bring my near zero in a meter or so.
Thane, Thanks for all the pictures, tear downs and commentary on this platform. The Bugbuster looks like it works really well!
I've recently acquired one and am curious how you removed the plastic end-of-barrel sight from the barrel shroud? Did you have to break it to get it off?
Thanks!
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It is A cap threaded into the shroud.
Takes some coaxing the first time off.
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Thane - do you think the PP750 is better suited as a .177 or a .22 given your experience with the .177?
Or is it too early to tell yet?
I ordered a .22 from Wes.
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I also have a 22 caliber one coming from Wes. Thanks for all the photos and testing. Very nice little pistol/carbine Thane. Those handle scales are awesome.
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I also have a .22 on order from Wes
.177 appears to have a small plenum volume, hoping the .22 is increased.
The baffles do a reasonable sound reduction in .177, @ .22 expect more noise.
Have to wait and see how it performs out of the box.
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I'll probably use a DonnyFL Tanto on it.
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Subscribing! Cannot wait till mine gets here.
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Like most budget guns the cocking action is not silky smooth. While it does smooth out a bit with use, some polishing and lube, there is definite coarseness to outright binding that can occur. This is exaggerated with higher spring tension, so it's time.
I first suspected the pellet probe dragging on it's metal collar, which could be replaced with a longer MDS collar which has helped Hatsan Flashpups. Nope, probe end completely retracts past collar and is only supported by the 1" ± wide portion of probe which has a machine bolt stud that catches against hammer sear ledge. When cocking the hammer spring force loads the bolt stud, skewing the pellet probe and dragging/binding in block. The machine bolt also had a very small overlap of hammer ledge wearing to a chamfer, I'm sure it was riding up onto the outer portion of the ledge making some occasional serious binding. Adding a 0.020" shim under machine bolt space increased the engagement. It is still rough cocking, but no more binding.
Some PTFE slides let into the probe would certainly help.
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Can you tell us more on how you made the grips?
Thanks!
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The grip scale material I used is stabilized wood and resin, bookmatched blanks sourced from Etsy.
Minimum blank dimension is 5" x 1 3/4" x 1/4" for OEM sized scale. To get out around the trigger with beefier section 5 1/2" x 2" x 3/8" (what I used, I've got big mitts)
Use thin 2 sided tape to join scale, exposed faces out, orientation of handle.
Remove right handle cover to use as template to trace LEFT (flat to flat) profile and drill points for fasteners through both scales. Use smaller drill, careful not to strip cover threads.
With blanks still bonded together cut and true profile, sand contours, chamfers... both left and right together. I use a 12" disc sander and 1" drum sander in drill press for undercuts, shaping finger and thumb rests. Resist making knife thin sections, they will break. Definitely wear a dust mask, who the héll knows what the etsy crowd used for dye/resin, you just don't need any of it in your lungs.
Separate and do some test fits on gun, feel for hand fit, finger and thumb shelve... what ever your working toward. Tape them back together and keep shaping until your happy with hand fit.
Break out the sand paper and hand sand until smooth. 220, 400, 600, 800, 1000, 1200
Separate scales and drill after sanding complete, this keeps bored edges from rounding, for correct hole size and countersink/counterbore to match hardware. I went with hex head countersink to keep more material under the head.
Then polish for resin, seal for wood. I took it to a satin finish and waxed it.
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Thanks Thane. I’m going to try it when mine arrives.
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Time for a cheek riser, bars are low and cold.
Drilled some high density polyethylene with a #1 bit (0.228") slightly under bar diameter 0.235" then wallowed it a bit left and right to maintain a friction fit. Bonded some EVA foam, shaped to correct height, can be rotated 180° for higher comb.
Works better than I expected as it greatly reduces the twisting and flex in retracting stock to an abso. Really wish I had done this first when added 2nd shorter stock index.
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I’m keen to order one of these from Krale shop soon. Very nice work. I’ve bookmarked and kept some photos from this page.
Do they also make a .25 or wastgat a different model. I really think .22 would cover my purposes
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I’m keen to order one of these from Krale shop soon. Very nice work. I’ve bookmarked and kept some photos from this page.
Do they also make a .25 or wastgat a different model. I really think .22 would cover my purposes
.177 and .22 available, waiting on a second PP750 in .22.
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To further reduce binding when cocking the PP750 I turned a tapered undercut (±15°) onto the hammer collar face and bolt head. Theses surface now dovetail together and do not allow the bolt to slide up on the hammer face edge.
With the dovetail cuts, bolt shim, some moly on thick section of probe... no binding for 200 or more pellets.
My PP750 was an early build and more recent builds may not experience binding, but if you do save your lever and take some action.
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To further reduce binding when cocking the PP750 I turned a tapered undercut (±15°) onto the hammer collar face and bolt head. Theses surface now dovetail together and do not allow the bolt to slide up on the hammer face edge.
With the dovetail cuts, bolt shim, some moly on thick section of probe... no binding for 200 or more pellets.
My PP750 was an early build and more recent builds may not experience binding, but if you do save your lever and take some action.
Nicely done!
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Thane son of Thanos,😁 been following this thread. Good work there guy. Looking to get one of these myself eventually.
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Thanks, it is a fun pistol to work on.
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Have you worked on the PP 700? Kinda wondering which can be made more powerful.
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Still would like this handgun if it can be made un-regulated and approaching 20 FPE
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Have you worked on the PP 700? Kinda wondering which can be made more powerful.
PP700 is one of my favorite guns, and others have pulled really high FPE out of. Like most I look for a balanced tune, finding what the gun feels comfortable to shoot at and where the sweet spot is for power/speed/accuracy/sound.
Common sense aside, the highest usable tune from my PP700 was 12FPE for 25 shots and best tune of 11FPE for 36 shots not so quiet. PP750 highest, regulator stack removed 16FPE at 2400psi with an 8.4 gr pellet, not at full pressure due to oring pressing out. Best PP750 balanced string 13 FPE for 28 shots 8.4 gr and very quiet.
I have little doubt someone will pull the washer stack, seal the air tube (it's open to allow the regulator to balance), slug the hammer with a brass core and make a Korean cliff starting over 20FPE and make a very loud sound come out of the 8" barrel.
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Thanks Thane. I'm still up in the air on which one to get. I like the seemingly simpler design of the 700 but also like the repeating ablitys of the 750. Well, I've got lots of time to think on it and info to read.
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Have you worked on the PP 700? Kinda wondering which can be made more powerful.
I have little doubt someone will pull the washer stack, seal the air tube (it's open to allow the regulator to balance), slug the hammer with a brass core and make a Korean cliff starting over 20FPE and make a very loud sound come out of the 8" barrel.
Perfect, that's exactly the way I like it :) ....1st shot the most powerful !!
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Mine hasn't arrived yet (sent to Brian for tuning), but I like the idea of crafting a cheek riser/rest. Maybe even making one that can fold out of the way so it can still be collapsed. Do you have calipers to measure the diameter and distance between the rods for the shoulder stock? I'd like to start designing one now if possible.
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Someone chimed in on the PP750 thread on AGN and stated he had seen where someone converted theirs to use a buffer tube and stock. That would be pretty cool specially if a guy could use a folding stock adapter. Such a neat little gun, I'm waiting on mine to come from Brian as well. The same guy posted a shot group at 25 yards with CPHP's the size of a dime! That's great news for me since I have a bunch of those pellets, like 11,000 bunch!
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Today the PP750 in .22 arrived from Wes!
Looks great, comes with USA brass valve seat.
First 5 shots with JSB .22 Heavy 18.13 gr made 450 FPS about 8.2 FPE... the starting point.
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Did yours go to Veradium? Try shooting some CPHP's.
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Straight to me.
I have some work to due to baseline it. Then it begins...
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Straight to me.
I have some work to due to baseline it. Then it begins...
After you have determined it will you please post the baseline info, Thane?
It would be most helpful.
Especially as a comparison for those of us that are having Veradium perform the tune.
Thanks
Ed
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Must be PP 750 Friday I got mine in the mail today also, shot some copper coated beeman 14xx gr through it to test function , in the basement, dang them Canadians like loud guns J/k.
Will crony tomorrow, so far nice .22 pistol/carbine for the $$, the retractable but stock seems much more solid that one review showed, one would have to pull it to your shoulder to the point of pain to get it to bow, it does have some side to side twist that is not an issue , may help custom fit to shoulder LOL.
Next up is deciding on optics, may cost as much as the gun :o ;D
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I received my .177 from Wes yesterday threw a scope on and sighted in at 15 yards it's shooting a pretty good group for not even cleaning it, only problem one of the magazines doesn't want to slide in and the cocking is really gritty feeling but I only had about 30 minutes to play with it so we'll see what today brings.
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I know that's one of the things Brian is going to address, the cocking lever. Congrats on the new gun. I'm sure you'll get it squared away.
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PP750 in .22 came with a rough crown job, no lands scoring so only a touch up to the factory crown, clean and polish 100 strokes wilt felt and bore polish.
Trigger takes some work to polish sear, round and polish very sharp tip on "first stage" set screw, polish tip on "second stage" set screw an then adjust for a very short first stage with satisfying second stage break.
Wes provided an USA brass valve seat with identical dimensions except for the exit ports.
Canadian: 1.80mm
USA: 3.44mm
Hammer spring came clipped, but has good tension and range.
Machined taper into hammer charge bolt head and matching undercut to hammer collar, reduces binding/drag.
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PP750 in .22 came with a rough crown job, no lands scoring so only a touch up to the factory crown, clean and polish 100 strokes wilt felt and bore polish.
Trigger takes some work to polish sear, round and polish very sharp tip on "first stage" set screw, polish tip on "second stage" set screw an then adjust for a very short first stage with satisfying second stage break.
Wes provided an USA brass valve seat with identical dimensions except for the exit ports.
Canadian: 1.80mm
USA: 3.44mm
Hammer spring came clipped, but has good tension and range.
Machined taper into hammer charge bolt head and matching undercut to hammer collar, reduces binding/drag.
So without a new brass insert, you could just open up the stock one a bit.
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You could, just drill out one hole... as long as your not in Canada... or other places.
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First shots out of the .22 PP750 with Canada 1.80mm port, no regulator adjustments factory set point @ 122 bar.
Hammer @:
0 turns in 450FPS
5 turns in made 480FPS (port is so small hammer adjustments make little difference)
Using the USA 3.44mm port, with no additional power mods, JSB Heavy 8.13gr made (this will be my baseline):
0 turns in 527FPS 11FPE
5 turns in 637FPS 16FPE (noticeably, much louder)
Filling to 200Bar shooting to 122Bar nets about 27 shots using 2 turns in on the hammer spring.
So far barrel likes: JSB heavy, JSB Hades, HN FTT 14.6, 3/8" 10 shot groups at 25 yds.
Right now the comfortable tune is 2 turns in with the HN FTT at 640FPS making 25 shots from 200Bar to 122Bar.
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You'll start working your magic on it soon Thane and have this thing shooting lights out.
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Some more .22 tuning this weekend.
Reached the end of hammer and regulator only tuning (JSB 18.13 used on all strings):
Pink Factory First String (2 turns,1700 PSI) 49 shots 13.5 FPE avg.
Blue Hammer Max (5 turns, 1700 PSI)28 shots 15.1 FPE avg.
Red Hammer Max, Reg 3/16 CCW (2030 PSI) 29 shots 16.3 FPE avg.
Opened plenum port to 4mm (obstructed by poppet spring)
Opened brass valve exit port from 3.5 mm to 4 mm (matches port to barrel thimble).
Opened/aligned transfer ports in barrel thimble from 3mm to 4 mm x2 (2 ports)
Regulator 5/16 CCW to 2030 PSI
Yellow Hammer Max (2030 PSI) 35 shots 17.6 FPE avg.
Extreme spread was all over the place, valley in string, double digit standard deviation. I suspect the hammer was struggling to open the valve.
Turned a 3.5 gram brass slug to add to the light 20 gram hammer and act as spring spacer (.22 has a thicker face than .177 hammer, requiring factory clipped spring).
Vented hammer face and slug with center drilled hole since valve stem is off center of hammer face, :P, but was much simpler than the channeling done on .177 hammer.
Big increases:
Green Hammer max (2180 PSI) 18 shots 21.9 FPE avg (it's loud)
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Thane,
You opened up the air path more on your .177, is there a reason for not going as much on the .22?
Great work btw, that 35 @ 17fpe+ is sweet..
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Thane,
You opened up the air path more on your .177, is there a reason for not going as much on the .22?
Great work btw, that 35 @ 17fpe+ is sweet..
Thanks!
I epoxied the .177 thimble port channel and second port making one large, aligned port. The 2 ports on the .22 have more area than a single, maybe some waste to the channel so I tried working with it instead.
The plenum volume was increased in the .177, which I didn't do in .22. I instead tried messing with hammer mass which paid off. I will be adding a brass slug to the .177.
Finding the fewest/simplest modifications with the greatest results takes a lot of attempts.
I expect to be tuning the .22 down a bit to a more balanced string, I'm sure at 22FPE my groups will suffer, my ears definitely are.
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Impressive results Thane! Keep up the good work.
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Thane
Did you make any baffles for the 22 shroud yet? Mine is pretty loud even in stock form.
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Just the stock baffles now. I have a Huma LDC waiting for an adapter. Noise really picks up once exceeding 600 FPS.
Just put a few JSB Monster Redesign 25.39 gr made 650 FPS/ 24FPE.
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WOW!!! That's a lot of energy for a little pistol/carbine.
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Just the stock baffles now. I have a Huma LDC waiting for an adapter. Noise really picks up once exceeding 600 FPS.
Just put a few JSB Monster Redesign 25.39 gr made 650 FPS/ 24FPE.
For about how many shots, you think?
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For about how many shots, you think?
Same set point as green string in chart, 18 shots on regulator with heavier pellet. Slower so it spends more time in barrel picking up a bit more energy.
Need to shoot some 25 yards groups at this power level, see if I can hold the groupings.
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For about how many shots, you think?
Same set point as green string in chart, 18 shots on regulator with heavier pellet. Slower so it spends more time in barrel picking up a bit more energy.
Need to shoot some 25 yards groups at this power level, see if I can hold the groupings.
Sure sounds nice, especially if they group. I'm still thinking over opening up mine, pretty daunting...maybe I'll just shoot it at the stock power level for a bit. A long bit. :D
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I just got a direct fit LDC off Ebay, put it on after taking a couple shots with the Rocker LDC , then the Ebay one, too close to tell if Rocker is quieter, but I will say it may be slightly :-\
But I need the rocker on another pistol LOL The Ebay is skinnier but about an inch longer than the Rocker one I have.
https://www.ebay.com/itm/SPA-750-ldc/174398475091?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 (https://www.ebay.com/itm/SPA-750-ldc/174398475091?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649)
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I just got a direct fit LDC off Ebay, put it on after taking a couple shots with the Rocker LDC , then the Ebay one, too close to tell if Rocker is quieter, but I will say it may be slightly :-\
But I need the rocker on another pistol LOL The Ebay is skinnier but about an inch longer than the Rocker one I have.
https://www.ebay.com/itm/SPA-750-ldc/174398475091?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 (https://www.ebay.com/itm/SPA-750-ldc/174398475091?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649)
James, Thanks for the direct fit link!
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There have been reports of poor functioning magazines, my .177 worked great and the .22 not usable.
The .22 mags would catch each pellet, jamming as it bit into each pellet. Opened up the mag and found that the port had not been de-burred or relieved in anyway.
Putting a slight chamfer on the port, polish and operates flawless now.
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Good to know! Thanks Thane.
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Bling for the PP750 in .22 and going more organic than the aluminum hex cells on the .177.
Sourced some stabilized blanks on Etsy. These are Banksia pods with an opalescent blue/black resin that has quite a bit of fire in sunlight.
The hand feel is very good, a bit of texture, thicker section and ambidextrous thumb/finger ledge. Additional DIY photos for those interested, can't wait to see what you guys come up with when deliveries are made.
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That looks great Thane!! You should make some up for us less skilled people to buy.
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Thane
Awsome grips. I looked on Etsy for the first time, wow a million choices. How thick were your blanks, to give you enough room for a thumb rest & finger grooves?
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Thanks, Mine are 3/8". 1/2" was my first set on .177, took a bit of thinning. 1/4" is too thin for a thumb shelve.
Blank sizes 5" x 1 3/4" x 1/4" for OEM sized scale.
To get out around the trigger with thumb shelves 5 1/2" x 2" x 3/8".
Etsy has an enormous amount, so does Ebay. Just verify overall size, some scales are small.
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Those grips are awesome! I would buy a set pre fabricated that looked that good. DANG!
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Those grips are awesome! I would buy a set pre fabricated that looked that good. DANG!
+1...
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So I had a 19" spare .22 barrel, turned and threaded it for the thimble, shot some strings.
I expected the much greater barrel volume (19" vs. stock 8") would starve the available plenum slowing velocity. Then I could cut down 1 inch see how much the speed increased, repeat until matched barrel volume to available plenum...
Nope, it picked up 13.5 FPS per additional inch of barrel, on high power tune ( 2100 PSI set, max hammer with 3.5 gram brass slug).
So now it's doing 32 FPE with JSB Heavy 18.13 gr for 19 shots 888FPS, punching way above it's weight class! Same 2100 psi settings push FX Hybrid slugs 22gr at 830 FPS / 33.6 FPE. Or 1,740 psi set point for 30 shots @ 815 FPS 26 FPE.
I will thread for LDC, add shroud and shoot as a true carbine for a while, see how it holds groups.
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Thane
I just polished up my washers in the regulator. When they came out they were not how I expected. Do you remember the sequence for your 22 cal? ))) (((((( )))
Thanks in advance.
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My .22 was the same as .177 )))((()))(((.
While your in the reg, take a pick and careflully drag the interior cylinder. Mine had lathe cuts you could feel. A light sanding with 1,000 oxide paper wrapped around wooden dowel flattened it smoothing the reg and opening the range.
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Thane
Thanks buddy, I'll do that. Loving the pistol!!
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Did you happen to count the turns to get it near factory setting?
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Did you happen to count the turns to get it near factory setting?
I disassembled my first PP750 reg without marking setting. Took several setting changes to find range again as entire range is less than 1 turn.
It is near brass flush with body. I now mark it with punch.
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Wow , that’s some serious power but not exactly a pistol any longer. Now we know that the valve train in the neat little gun will in fact Take to mods very well. I wish they made a rifle version of this one so I could play with it.
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Wow , that’s some serious power but not exactly a pistol any longer. Now we know that the valve train in the neat little gun will in fact Take to mods very well. I wish they made a rifle version of this one so I could play with it.
Well I am still having a blast with mine shooting 500 FPS ;)
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Wow , that’s some serious power but not exactly a pistol any longer. Now we know that the valve train in the neat little gun will in fact Take to mods very well. I wish they made a rifle version of this one so I could play with it.
Power is there, even with a minuscule plenum.
The long barrel was to find performance limits, very accurate and terrible in the hands.
I have now cut it down to 11.5", which is the full shroud length plus 1/2 20 threads for LDC, much better.
At 11.5" it can make 25FPE with 790FPS using 18gr pellets for 22 shots/3mags.
My preferred tune is 20 FPE at 710FPS for 31 shots. This tightens my groups to 1/4" ctc at 25 yards. The added weight in the front helps.
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It is a thick barrel.
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After several attemps I ended up setting the regulator around 115 bar. Using a chopped off rounded bolt head I made a hammer weight with caveman tools, and flattened the spring end. I opened the passage & the valve to 4mm and shaped the flow, polished the regulator washers & smoothed the walls. I replaced the trigger spring with a lighter one, and polished the action, sear, and trigger screws. I was able to adjust the pull to about a pound or less and still retain the function of the safety.
Thank you Thane, for leading the way. I now have a really smooth pistol with a great trigger. With the hammer spring backed all the way out, I get 35 shots @700 fps (Crosman domes) and another 5 between 680 & 695. I still have plenty of room to up the hammer spring, or the regulator, but for my backyard pesting, this is perfect.
The pp750 is a great platform, easy to work on and understand. It's not bad right out of the box, but with a little tweeking and TLC, it feels down right refined. I love this little guy, and it is quickly becoming one of my favorite open sight (red dot) pistol/carbines.
Has anyone tried the Carm magazines yet? I know that they only hold 6 rounds in 22 cal.
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Has anyone tried the Carm magazines yet? I know that they only hold 6 rounds in 22 cal.
I picked up a pair to test out, and couldn't be more satisfied. Never really cares for the style that came with the gun, and being so small, just add to my dislike.
The Carm magazines are a much better design imo, and work flawlessly, at some point I'll pick up a couple more.
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Hello PP750 owners,
I got the bug for a PP750 after having so much fun with my PP700SA.
If I get it from Wes in Canada do I get a de-tuned Canadian or Eu version?
I realize it can be tuned / adjusted for more that 500fps but do they all come that way?
Thank You
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Yes due to CA laws pistols can not exceed 500 FPS, Wes at AAF may still give the option to ship direct to a tuner for power upgrades, just send him a PM.
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I bought a PP750 22 from Wes
It comes Canadian tuned with the parts to upgrade to USA power levels
I'm not sure if that's simply a transfer port or a different valve, or both: because mine has been sent directly to Veradium Air for a tune up
Wes at airgunarcheryfun.ca can answer any questions and is fantastic to do business with.
Ed
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I'm a fan of Wes and his business practices. Really do not want to send it out for an uptune.
Transfer port and valve are likely easy enough to to change. I'd LIKE to buy one made for the USA market.
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I received mine with the Canadian tune but Wes also sent a valve body that is for the American tune, I just got back from vacation so I'll be playing around with it now this is a great thread for learning how to work on this pistol, Oldpro has started one also.
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Getting a PP750 gets me three things:
1) I'm no longer the only guy that doesn't have one ;) ;) ;)
2) A shroud that reduces report
3) Multi-shot
On the PP700 I have a rifle stock configuration that I love, accuracy, shot count and FUN. This purchase would be for tuning it to max power and popping ground squirrel from my truck and I'd want to add a longer barrel and that cancels the shroud benefit. It's starting to look a lot like another rifle which I already own two other tack drivers.
I think I talked myself out of it.
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I saw the tuning post by OldPro and it's quite impressive.
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15 minutes ago I nearly pulled out my credit card to get one from Wes.
I'll ponder it some more
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Jonny
You're going to open it up anyway, to drop the valve in, you might as well go for it while you have it apart. It's such a fun gun, you won't regret it. Thane got pretty good power, even with the stock barrel, and the shroud DOES help a bunch with the report. Add a moderator and you're golden. I'm looking to get one (short moderator) with male threads to eliminate the adaptor, but it's backyard friendly as is.
My job (as an enabler) is done!
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Jonny
You're going to open it up anyway, to drop the valve in, you might as well go for it while you have it apart. It's such a fun gun, you won't regret it. Thane got pretty good power, even with the stock barrel, and the shroud DOES help a bunch with the report. Add a moderator and you're golden. I'm looking to get one (short moderator) with male threads to eliminate the adaptor, but it's backyard friendly as is.
My job (as an enabler) is done!
Thanks Mike. You've done a great job of enabling. I put a DonnyFL Tatsu on the PP700 and it's pretty good but I ended up with more moderator than gun, eventually. Very backyard friendly
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I have been shooting mine long enough to say the PP 750, dollar for dollar blows the P-rod away, Glad I bottled my P-rod before getting the PP 750 ;)
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Getting a PP750 gets me three things:
Johnny,
I am very curious how the two compare. On the face of it the PP750 is much higher value. That is, if it works as well as the PP700.
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Here is my PP750 (I got it week ago) add some stops on the rails and I can adjust stock opening. I install 4x32 scope from KONUSPRO.
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Getting a PP750 gets me three things:
Johnny,
I am very curious how the two compare. On the face of it the PP750 is much higher value. That is, if it works as well as the PP700.
Me too. If it works as well as my PP700 then it's certainly worth the price difference. If I needed it.
After further pondering I realized that I almost NEVER get a second shot, on a miss, or another rat or ground squirrel so I therefore don't NEED multi-shot and my LDC is effective, likely much more so than the 750 shroud. I talked myself out of it.
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Johnny, Johnny, Johnny
I'm not doing a very good job as an enabler if I let you decide based on your NEEDS. You "need" to get a 750 and work it over. You'll fall in love with it due to the fun factor! It's a blast to shoot. The fact that it's a multi shot with a lever action is a big part of that fun. Sell your 700 & let someone else enjoy it, while you eradicate every pest with a quarter mile.
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Here, here, I second that!
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JUST buy it! You wont regret it
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No pressure here ;) ;) ;)
The 750 is still on my radar. I NEED a water cooler for my TIG welder first... Aluminum welding is HOT and may damage my pellet inserting thumb
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Johnny
Duck tape around thumb! Several layers. Use savings to buy 750.
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Johnny
Duck tape around thumb! Several layers. Use savings to buy 750.
LOL x 10, Thank You.
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You guys are the worst enablers in the world!
(in a good way...) ;)
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I like the extra notches on the stock. Always good to have options.
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I was thinking about notching mine a few inches from closed, to possibly work as a wrist brace in pistol mode.
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The extra notches is a great start to making this gun exceptional since the stock scope mounting options are so limited and the original length of pull so long.
For short range/slower guns I like using smaller scopes and keeping the height as low and close to bore as possible. This keeps the shot flat and in Killzone over a longer range of distances. The magazine projects up basically locking the scope in one position, limiting fore and aft eye relief adjustments. So adjusting the stock distance is the compromise that works.
Adding a cheek piece locks out the twist in the adjustable stock, approaches fixed stock stiffness.
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I got my PP750 only couple days ago and right next day a very first surgery was done (deburring, polishing internals) and a very first oring is blown :).
Ordered some springs in couple different sizes (hammer and cocking and trigger control, you know).
Looking at that shroud (Canada here), to much empty space inside, my best guess to go for a 12" barrel, only not educated where to look for blanks? or older brakebarrel for parts? Me coming from Lego Impact, that aftermarket is well innovative.
Where to look for and what to look in for that 12" barrel?
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...no regulator adjustments factory set point @ 122 bar.
...
...25 shots from 200Bar to 122Bar.
Thane, how do you measure the regulator pressure? Only recalculating from fill 200 bar to a drop to 122 bar? or you have a "device".
I cannot imagine attaching a little gauge only to redesign the "plenum" block.
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Looking at that shroud (Canada here), to much empty space inside, my best guess to go for a 12" barrel, only not educated where to look for blanks? or older brakebarrel for parts? Me coming from Lego Impact, that aftermarket is well innovative.
Where to look for and what to look in for that 12" barrel?
You might consider an LW barrel. It would take some machining, so depends on whether you can manage that or not. I ordered a blank in .22" for my QB78D a few years back. Took some cutting and refining to fit the receiver and develop an appropriate chamber, port it, cutting a nice crown, and threading for a muzzle brake, but was very much worth it on that rifle as accuracy was much improved. A Redman's .22" barrel liner might be another option if you wanted to epoxy on a carbon fibre tube over it. And there are the Crosman barrels of course. Scopes & Ammo have a selection of those:
http://scopesandammo.com/storefront/index.php/airgun-parts-custom-service-crosman-barrels-c-38_70 (http://scopesandammo.com/storefront/index.php/airgun-parts-custom-service-crosman-barrels-c-38_70)
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I got my PP750 only couple days ago and right next day a very first surgery was done (deburring, polishing internals) and a very first oring is blown :).
Ordered some springs in couple different sizes (hammer and cocking and trigger control, you know).
Looking at that shroud (Canada here), to much empty space inside, my best guess to go for a 12" barrel, only not educated where to look for blanks? or older brakebarrel for parts? Me coming from Lego Impact, that aftermarket is well innovative.
Where to look for and what to look in for that 12" barrel?
11.5" barrel clears shroud about 3/4". No porting or lead work to do, but you will need to turn it down and thread to match thimble at least.
I repurposed a Hatsan barrel with very accurate results. A longer barrel can give you more power and efficiency over the 8" stock barrel.
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...no regulator adjustments factory set point @ 122 bar.
...
...25 shots from 200Bar to 122Bar.
Thane, how do you measure the regulator pressure? Only recalculating from fill 200 bar to a drop to 122 bar? or you have a "device".
I cannot imagine attaching a little gauge only to redesign the "plenum" block.
Shooting a string with a chrono take note of the gun's pressure gauge when the velocity pitchs up, then drops or maybe just drops. Right before that the pressure gauge is reading the set point.
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...It would take some machining, so depends on whether you can manage that or not...
Yes I can manage machining, also have a micro mill for quick ideas and easy fixes, unfortunately no lathe on my own but have access.
You might consider an LW barrel...Redman's...Hatsan...Crosman....
Thanks, I need to look around which one I can get easier.
Looking into this little #66 block now, I have couple FX gauges from my LEGO gun laying around may have a good use for that. I would redesign/make that #66 bigger, missing some arca or picatinny rail on the pistol anyway I may combine together?
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I just purchased a trigger spring from Hawkeye51. WTS ** Lighter trigger spring ** for the SPA pp750 - Airguns & Guns Forum (gatewaytoairguns.org) (https://www.gatewaytoairguns.org/GTA/index.php?topic=179985.0)
It made the trigger feel much better and I tuned it down to 1lb 3oz. :)
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Has anyone tried the Carm magazines yet? I know that they only hold 6 rounds in 22 cal.
Carm now has large capacity mags for the 750. They Hold 12 in .22 and 14 in .177. I haven't tried them yet but have a couple on order.
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Has anyone tried the Carm magazines yet? I know that they only hold 6 rounds in 22 cal.
Carm now has large capacity mags for the 750. They Hold 12 in .22 and 14 in .177. I haven't tried them yet but have a couple on order.
That is a great capacity increase. Let us know the dimensions beyond original mag, my scope is that close.
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Has anyone tried the Carm magazines yet? I know that they only hold 6 rounds in 22 cal.
Carm now has large capacity mags for the 750. They Hold 12 in .22 and 14 in .177. I haven't tried them yet but have a couple on order.
That is a great capacity increase. Let us know the dimensions beyond original mag, my scope is that close.
The CARM website indicates that the larger capacity PP750 magazines are 13mm taller than the others for the gun, for a total height of 40mm
Here's the link
https://www.carm-magazines.com/high-capacity-carm-magazine-for-pp750-air-pistol.aspx (https://www.carm-magazines.com/high-capacity-carm-magazine-for-pp750-air-pistol.aspx)
Ed
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I had to measure but I think I'm good. I have one set of rings taller if not.
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Current scope centerline is 1.4" above bore, low as it will go over mag, only 1mm to spare.
Keeps near zero close, great advantage for 8- 30 yard shooting
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Wondering if this my rev.6 plenum block can double the shot counts ? :) sourcing tomorrow and hoping to get back with some numbers soon.
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Double would be great!
Looking forward to your strings
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HI It got quiet here.
So what I had done:
All ports opened /drilled
Pallet bridge 3.5mm OD to match diameter off channel in stock.
TP port drilled to 4mm OD I would recommend not to drill any bigger and keep slight angle or you will drill to outside.
I had polished hammer and popet / transfer port shaft. 1200 wet sanding.
Without touching regulator it brought me to 19.6~20.1 FT/LBS with 12 stable shots. with JSB 18.13grain
Now to work
I had turn regulator down to full turn and half.
still 420FPS bit to much for 6FT/LBS in UK, also lots of air still wasted.
Hammer spring consistently shortened one whole link tested at 40 shots series (from chrono I can tell my reg is about 70bar)
After 4 cuts I stared to see massive improvement.
Gun is incredibly quiet now I had gone 50 shots in 18.13g and I'm out off ammo now, gauge still on 180BAR.
I hope for nearly doubling shot count and fun.
I will order LW long barrel and mode/adjust to 350mm length, then I will bring it to 12FT/LBS.
I will keep it posted
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Nice tuning, especially with stock barrel!
I currently shoot at reduced power to 16.3 FPE for 55 shots averaging 635FPS using extended barrel with JSB 18.13, it's favorite pellet.
It is amazing the range of tune this little gun will support.
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So There we go ...
I'm so happy because its my first tune ever.
I am getting 150 shots from that pistol. LOL
JSB 18.13g 402FPS on average with 8FPS spread
JSB 15.89g 414FPS on average with 12FPS spread
JSB 14.35g 445FPS on average with 14FPS spread
I forgot to mention yes its in .22 I am wondering what you can squeeze from .177 ???
IF any one attempted max shot count in .22 or .177 please post.
Grouping on 20 meters with red dot amazing.
I had 80 consecutive shots in 10p coin.
Idea is brewing to make cnc alu bridge port for bigger 0.3L bottle. with digital gauge etc.
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First shots out of the .22 PP750 with Canada 1.80mm port, no regulator adjustments factory set point @ 122 bar.
Filling to 200Bar shooting to 122Bar nets about 27 shots using 2 turns in on the hammer spring.
So far barrel likes: JSB heavy, JSB Hades, HN FTT 14.6, 3/8" 10 shot groups at 25 yds.
Right now the comfortable tune is 2 turns in with the HN FTT at 640FPS making 25 shots from 200Bar to 122Bar.
I went through some pallet samples. I did some job on crown and that is result. This RS JSB are amazing I got near zero flyers.
I'm set to 500FPS div have cleaned regulator and changed seal on reg head. Divination i get is between 2 and 4 FPS depending on string .
I do discard firs 3 shots after refill cos they always of chart. It gives me 80+ shoots.
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Piotr
Great results shown in the above post. For using a red dot, it's hard to be more accurate than that. Quite interesting these little pistol/carbines can have such a wide range of tuning. Most guys are tuning up for power, but you have tuned down for shot count and still have enough power for pest control. Well done!
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Well it has been a bit over a year since I got mine in .22, shot it factory stock for most of the warranty period, while gathering a 16" barrel and assorted LDCs etc..
The other day I had air escape while plinking in the cold, with the 16" barrel it was shooting around 585 fps, with Canadian parts 16 gr AA pellets and the longer barrel, gained 85 fps.
Took it apart opened up the barrel and TP to the same as Thane did, but left the grooved thimble 2 ports as is, set the reg at about 150 bar, 2 threads showing on reg adjustment screw. now getting 18+ shots at 830 fps, 24.4 FPE with 16 gr AA pellets, need to test more ammo as this is a fresh barrel and new tune, so there is that fun task to do yet.
All in all it is one of the easiest PCP air rifles I have taken apart. No screw heads that easily strip like say a Prod. 8)
PS From my findings the air leak was from a loose screw on the block that leads to the poppet/ valve area, that allowed air past the oring seal.
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=8209)
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James
Tell us where you sourced the barrel and did you thread it to fit or bought it threaded. Have you streached it's legs yet? Like 50 yards or so.
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Ready to screw on from here https://airgunarcheryfun.ca/pp750-long-barrel-16/
Have not gotten past 10m with it after mods, cold weather old n all ;)
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Thane I have to say there is lots to blame you for.
1 I have mini Chinese monster in my front room
2 I have ordered all needed tools for it which was more than lathe itself
3 I never used it before so i have lots to educate myself! nights are short now very short
I had manage to fit 630mm .22 blank on that ?pistol? it was fun till 3 hours later.
I did cut barrel so choked part to be 11 inch siting in shroud. Second part of blank will is unchoked and will be subject to experiment with slugs.
I will post soon ....
broke my insert and still waiting for new 4jaw independed chuck
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Looking at Piotr’s pistol I can’t help but wonder
Is there a longer air tube we can use?? With the longer barrel it just seems like we should be able to put a bigger reservoir on.
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Yes you can get one from other air gun makes or go china .com
tube of 500mm length up there is about $39
I am looking forward to make Z-valve rearrangement and hung on with 500cc carbon bottle :D
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@PiotrBBurzy looks really good!
Enabling is one of my skills...
I am amazed how small the plenum is and how much barrel it will support.
The Umarex variant will bring even more modifications, fun times.
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Wondering if this my rev.6 plenum block can double the shot counts ? :) sourcing tomorrow and hoping to get back with some numbers soon.
I just got devastating news from WES ... it looks like my plenum is missing in transit.
Bit off shame I was going to set it with other barrel I have prepared for slugs.
FFS I was hunting for it since summer.
I will put together some new finds about this "pistol".(groups with chocked weihrauch barrel and some works with carbon silenced shroud)
I had experimented and have shoot some unregulated with leaded hammer and custom springs. Have to say I had pushed it to 36 FPE.
Yes it kicks :)
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Some show-off I can turn some of things in my to small lathe :o
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Piotr
I like it !!!
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So I have some news.
First there where issues with my first version off carbon shroud. It was very nice and quiet but I have noticed it was LDF was clipping my pallets:( Holly grail of lathe works ... concentricity is must and always checked. But my skills improving quickly. I run two barrels made of one length 630mm Weihrauch blank. So i have choked and unchoked setup.
I had reworked all idea setup and I have end up with barrel tensioner. At the time i had no clue it will work that way. Recently i was watching FX development of barrel tensioner for 800mm long barrels.
I started to play with it and it works you can tighten your groups:)
Now no bottle yet but I will come eventually. Gun reg is set 100 bar its Huma but now I agree its not must as original reg is very good quality.
I have hammer drilled and led washers pushed in. Hammer spring is changed to. Spring behind poppet valve changed to lighter one too. You don't need that original monstrous. Valve will close under pressure any way. from full fill it gives me 70 shots in 12FT Lbs. Just to stay with UK boundaries.
Thanks to Wes (amazing service and prompt answer to all questions highly recommended) I have bigger plenum and gauge on reg.
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And some photos of my tinkering attempt.
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Slugs at 30 meters.
18 shots on average with 18.5FT/Lbs
JSB KO very nice grouping. I was taken a bit by surprise how it kick a gun.
I have also checked if pallets will hold and well well well. They do!
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Nice 30yd slug groups!
Great pesting gun.
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Some changes to the PP750 in .177 for Pistol Field Target:
Bottle drop block with adjustable Ninja Regulator and carbon bottle.
Carm single shot loader.
16mm Lothar Walther slow poly barrel 14.9 inch length removed thimble and threaded blank to insert directly to breach block, added transfer port.
1/2-20 slip on adapter for practice moderator, too long for competition rules.
Dovetail slip on over barrel to move scope forward.
Makes 12FPE limit easily @ 1250 PSI, 3/8" ten shot groups at 35 yds.
Learning consistent holds is something I am still working out.
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That pp750 looks awesome. Where did you get the drop block?
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That pp750 looks awesome. Where did you get the drop block?
https://www.amazon.com/gp/product/B0BLHFKY4R/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1 (https://www.amazon.com/gp/product/B0BLHFKY4R/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1)
You will need to run a tap to finish out threads, and shims or surface down face of block to clock it when it seats.
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I just saw another PP750 bottle conversion, seems to be the same setup used on the Notos. I just bought an Air Force clone that uses the same regulator.
https://youtu.be/v_6QnMw3h14
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It's been 3 years, but I finally got around to buying a PP750. More than a year into this stage 4 kidney cancer diagnosis thing I'm getting itchy to do something other than take medications, rest too much, and cram in the odd bit of actual work to pay the bills. Modding an airgun for fun will be just the ticket.
I didn't see this Youtube video in the thread, though it's possible I missed it. This fellow goes through all the important power modification possibilities, showing every element quite carefully so as to avoid confusion due to terminology or descriptive phrasing. He doesn't fill in the inlet channel around the barrel as someone in this thread mentioned, and that does seem to me to be a good idea. I'll be marking for alignment and filling the channel with JB Weld steel-filled epoxy, and if one of the two holes doesn't happen to align properly, will drill a third through that.
For someone like me who is very visually oriented, the many pictures in this thread are a huge help... but nothing quite as easily interpreted as a video I can pause and back up at any time. So I saved the video to my computer for reference as I go along. Also wondering about adding a short length of stout 6061 tubing to increase plenum volume, but I'm unclear on the layout, and suspect that may not be possible with this threaded-together installation, though I think I did see a threaded plenum extension on eBay that might fit, not sure. Already ordered a PEEK valve from a hobbyist seller there. And the pistol should arrive in a week or two. Very excited!
https://www.youtube.com/watch?v=U5hmeDDadqg (https://www.youtube.com/watch?v=U5hmeDDadqg)
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Thanks for posting this video. Somehow I missed it. Happy 2024!
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Well I've tinkered and fussed and adjusted my PP750, and have it dialed in at an efficiency level far better than factory settings. Opened up all the ports to 1/8", including the aluminum offset transfer chambers where the hole is at the top edge of one side's hole and the bottom of the other side, using the drill on about a 15 degree angle to avoid touching either inside diameter surface. The objective here was not more power, but a smoothed-out air supply, with which I could then play around at the striker end.
The thing came to me shooting 8.43gr JSB .177" pellets at about 515fps - a hair over the Canadian regulation, silly Snowpeak, seems their 1mm hole in the brass valve wasn't quite small enough. It was LOUD at 515fps! Ridiculously loud. Hence my exploration of efficiency. By the way, adjusting the hammer spring bolt wasn't possible, as the grip frame blocks it from coming further out than flush. I'd have had to cut spring coils off to get it below 500fps.
So with all the guts worked over, thinking of all the successful, highly efficient tunes I've done on a Brocock Atomic, a Crosman 2240 and 2260, a QB78D (all converted to PCP, the last with a Ninja bottle), knowing how a much lighter striker 'tickling' the valve stem instead of bottoming it out (thank you again, Bob Sterne, for the innovation of the SSG, which has given me such great results in a bunch of airguns), I made an aluminum striker. Copied the stock steel one exactly in 7075 aluminum, then bored a pocket in the striking face and drilled and tapped for an 8-32 stainless steel bolt with a large round head, ground that past the slot once the JB Weld was cured, and had my hard striker face. The new striker weighs 8 grams, compared to the 20 grams of the stock steel one. And out of concern for wear on the sear-catching edge, I polished the sear nicely - it was rather rough from the factory, surprisingly. The trigger dropped about half its resistance as a result, from about 7lbs to 3.5lbs. And inspecting the striker's edge after around 50 shots I could see no trace of wear, using a mixture of lithium grease and bike chain oil as a lubricant to keep things smooth in there.
The thing now *sips* air, shoots magazine after magazine with the gauge barely dropping... I've not bothered to shoot it all the way down to regulator level (stock setting is about 120bar from what I can make out - I polished the edges/centres of the bellevilles, so may have shifted this slightly), as I'm too cheap with pellets these days. It's just shooting an awful lot of them, which is great, because the kidney cancer which is spread around in my guts makes running the Hill pump somewhat painful. Hoping the new drug they've got me on will calm that down soon - already improving after three weeks on the awful stuff. Maybe by spring I can pump up my airguns without feeling it for an hour afterwards. Meantime, this Artemis is a joy to shoot, so I'm happy I finally bought one. And I'm happy to report that the *report* of the pistol sounds a little more reasonable for the low power level. Maybe half as loud as factory stock. That's what you get for not using a heavy striker to waste a bunch of air long after the pellet has exited the barrel.
Next up, I just bought an Edgun Leshiy 2 from a guy in another forum. Should ship tomorrow. I won't be needing to modify anything there! Just something I've wanted since it came out, after wanting the original Leshiy since it was in prototyping, and never had the opportunity to buy due to inconsistent finances, or the government ban on the original model, or stores always being out of stock. This one's barely used, in .25", at about 2/3 of retail, so I'm happy I'll finally get to shoot a Leshiy - at least more than the 4 shots I got to try back in 2019 at our monthly HFT gathering. Couldn't miss with that thing at 50 yards offhand. Ridiculously nice gun, and a marvel of engineering.
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Spoke too soon on the sear marring the aluminum striker - after about another 70 shots I pulled it apart and found some slight rounding at the edge where the sear slips past, so obviously not going to last very long.
Found a thick stainless washer of decent hardness in my parts bins and turned the middle out to a press fit, snugged that up against the flared end after turning down about 2.5mm of aluminum to make room. Then drilled 4 x 1/16" holes around it and put short sections of finishing nail into them, required hammering them in against a drill shaft then hammering some more to flare out both ends flush and keep the pins in place. That should do the trick.
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Did anyone tried to polish the tube where the hammer slides? Is is made od steel or aluminum?
I polished the hammer but I noticed the tube surface is pretty rough, too. Might benefit from polishing?
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I doubt the finished inside surface is causing any significant friction on the hammer. A trace of some lubricant ought to be enough to ensure the hammer drops easily and consistently. My measured velocity strings show very small variation shot to shot, easily accounted for by the need for the regulator bellevilles to wear in and become smoother, even though I polished them at contacting areas. And this is with my aluminum hammer, less than half the mass of the original steel, where friction would show up as a higher percentage of velocity change compared to the steel if it were an issue.
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I made a small modification to the buttstock, as it bothered me that leaving a magazine in the receiver meant either firing a shot, or leaving the gun cocked. I'd rather have the full 9 shots available. And carrying magazines... where? In a pocket? Sure, for extras, but for the one I will want to use first? So I drilled and carved the aluminum of the butt plate and used tape on a magazine, coating it with a beeswax/mineral oil paste that I use for lubricating zippers on instrument cases, so that it would not stick to the JB Weld steel-filled epoxy I used to fill the voids in the plastic and make for a neat fit. Pushed in a small neodymium magnet to retain the magazine. Works great, can't fall out but is easily lifted out by tilting from one edge, and doesn't get too close to the grip when closed, even though I replaced the big steel knob with a small bolt to allow the stock to close an extra 1/2".
Oh, and I found a neat little scope on eBay for $75, shipped. The size seems right for such a small airgun. It's a 3.5x prism scope, with 3-colour illuminated turret. 3 brightness levels each on red, green, and blue, with no illumination (off) between each colour on the dial. Should be handy for any sort of lighting situation. Next up - figuring out an adapter to get my infrared monocular/illuminator thing to fit to it for ratting.
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I doubt the finished inside surface is causing any significant friction on the hammer. A trace of some lubricant ought to be enough to ensure the hammer drops easily and consistently. My measured velocity strings show very small variation shot to shot, easily accounted for by the need for the regulator bellevilles to wear in and become smoother, even though I polished them at contacting areas. And this is with my aluminum hammer, less than half the mass of the original steel, where friction would show up as a higher percentage of velocity change compared to the steel if it were an issue.
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I guess you are right then. So, how satisfied you are with aluminum hammer now that you sorted the galling issue?
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I'm rather happy with this setup. Efficiency of 1.15 fpe/ci isn't hugely successful compared to something like my hyper-efficient QB78D where I get 1.87fpe/ci, bur for a short barrel like this it isn't terrible.
Bob explains efficiency here for anyone not familiar:
https://hardairmagazine.com/ham-columns/pcp-efficiency-what-is-it-what-changes-it/
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Here is my PP750 with bottle mod- 16 inch .177 and .22 barrels from WES at AIRGUNARCHERYFUN - custom barrel band with pic rail from HOTSNOTS and custom side lever made from aluminum angle and hand tools. It right now in .177 is shooting 10.5 at 855 FPS.
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Should I buy the 10.5" barrel? How much more fps?
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I seen some where it makes difference for the good and speeds it up. I got the 10.5 barrel from Wes but have not tried it yet. I need a Crony to test, up here in Canada we need to stay under 500 fps so no help. but I did learn that the torque is hand tight and a bit. And that’s why I joined GTA so welcome to the GTA.
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I'm waiting on the 10.5 barrel from Wes. Here in Greece we have no fps limitation. Thanks for the reply.
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Very cool you will not be disappointed, Wes is the Best, I bot a muzzle brake and it makes my pp 750 look complete. I still need that crony so I can’t do mods yet. Maybe for Christmas? Let us know what you think when your done testing your Mods. Happy air gunning.
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I would also like to buy the gauge blocks when they become available again. I can't see how accurate the regulator setting is.
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Ya Wes has to work his butt off to get stock but it will come. The gauge on the block look like a standard 0 to 300 bar or you can change it I think, ask around I am no expert be safe thats why I joined GTA. I think it’s bin about a year, not that I have the funds and I am saving of that crony first hehe. I want to stay within the law don’t want mess up are sport it’s hard enough now. but yes I will try one if I can get my hands on one. I would like to add a moderator or silencer but for now we can’t. Are speeds here is a bit low and the tree rats can hear them coming so you have to be extra sneaky, look like a tree. Also they look cool. Happy air gunning.