GTA
Airguns by Make and Model => Vintage Air Gun Gate => Topic started by: Tack Driver 10 on December 29, 2019, 08:10:02 PM
-
Picked up this 312 earlier this year from a GTA member.
It's in pretty good shape with a nice stock.
The pump link has issues along with the safety.
The pump arm walks out every few seconds so the check valve is leaking.
Took the gun apart and cleaned the parts.
The internals look good with no surprises.
I could just replace the check valve and put it back together but.....
The plan is to replace the heavy spring in the valve with a lighter spring and make a new valve seat.
The seat will have a concave seal and Delrin stem.
It'll be similar to the 317 valve mods done earlier.
https://www.gatewaytoairguns.org/GTA/index.php?topic=160425.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=160425.0)
-
Made a new check valve from Teflon.
Set it with a brass plug and dowel.
The brass plug is similar to a PA.
This is a test version to see if the gun seals.
Put the gun together and it sealed fine.
Next need to replace the heavy spring in the valve with a lighter one.
Not sure if I'll make a new valve seat or leave it stock.
-
Always good to see a highly skilled mechanic at work. Thank you for sharing!
-
Decided to utilize the stock valve seat for now.
Why recreate the wheel when you can just put a new tire on it....LOL
Turned some #22 drill rod down to .125" and pressed on a Delrin blank.
Machined it to .250" diameter and cut the stem seal with a contour to match the valve seat.
Temped it in the gun to see if it would hold air and it did.
I'll let it sit overnight before it gets the thumbs up.
-
The gun held air overnight so put it together and ran it over the chrony.
With 14.3 CPHPs
03 pumps 402 FPS 5.13 FPE
05 pumps 473 FPS 7.10 FPE
07 pumps 524 FPS 8.72 FPE
Respectable numbers.
Next I'll open up the front end and pull the piston.
Felt like the gun had a lot of dead air when pumping.
-
I imagine a new pump seal will bring the velocity up a bit.
-
Pulled the piston, seal looks pretty good.
This gun must have spent a lot of time in Seattle because there was a ton of grunge in the felt oilers....LOL
Soaked them in mineral spirits and then a stimulating bath in the ultrasonic cleaner.
Now they're squeaky clean as a whistle.
The pump link is the biggest challenge on this gun.
Looks like a gorilla with a bad attitude got a hold of it....LOL
No problem, I picked up a like new replacement earlier this year.
Put a test piston and seal in the gun to see what it can do.
Same test piston I used on one of the 317s.
-
looks awesome !
-
Impressive looking work, as usual!
Curious why the holes in the face of the piston seal? Won't that create necessary head space?
-
Impressive looking work, as usual!
Curious why the holes in the face of the piston seal? Won't that create necessary head space?
Good question which was brought up with the 317 I worked on recently.
https://www.gatewaytoairguns.org/GTA/index.php?topic=160425.msg155787521#msg155787521 (https://www.gatewaytoairguns.org/GTA/index.php?topic=160425.msg155787521#msg155787521)
The pump link would never support a highly efficient gun building 2000+ PSI with a FT setup.
It would bend like a wet noodle so best to incorporate some dead air to provide some cushion for the pushing.
Also the pump tube will flex and the solder joint between the tube and barrel will fail if pushed hard.
This gun is a 53 year old classic that is best improved with modern materials to hopefully last another 47 years.
That would make it 100 years old in 2067.
-
Impressive looking work, as usual!
Curious why the holes in the face of the piston seal? Won't that create necessary head space?
Good question which was brought up with the 317 I worked on recently.
https://www.gatewaytoairguns.org/GTA/index.php?topic=160425.msg155787521#msg155787521 (https://www.gatewaytoairguns.org/GTA/index.php?topic=160425.msg155787521#msg155787521)
The pump link would never support a highly efficient gun building 2000+ PSI with a FT setup.
It would bend like a wet noodle so best to incorporate some dead air to provide some cushion for the pushing.
Also the pump tube will flex and the solder joint between the tube and barrel will fail if pushed hard.
This gun is a 53 year old classic that is best improved with modern materials to hopefully last another 47 years.
That would make it 100 years old in 2067.
Makes perfect sense. Always wanted one, but never ran across one at a decent price.
-
Ran the gun over the chrony with the test piston and new pump arm.
Previous results in ( ).
With 14.3 CPHPs
03 pumps 426 (402) FPS 05.76 (05.13) FPE
05 pumps 528 (473) FPS 08.85 (07.10) FPE
07 pumps 602 (524) FPS 11.51 (08.72) FPE
Was able to straighten the original pump link, good pump link for an everyday shooter.
-
Very nice work and nice gun!
-
Ron... That gun really looks familiar. You got it in the exact condition I received except for that safety. I assure you that it wasn't like that when I packed it (presuming this is the gun you got from me). Either way, I'm glad it's in your hands and will get what it deserves. I've followed many of your builds. Looking forward to what you do with it. And yes, the wood was surprisingly nice. IIRC, it looks like at some point someone had a butt plate screwed onto it the plugged the holes..... my memory ain't what it used to be.
-
Ron... That gun really looks familiar. You got it in the exact condition I received except for that safety. I assure you that it wasn't like that when I packed it (presuming this is the gun you got from me). Either way, I'm glad it's in your hands and will get what it deserves. I've followed many of your builds. Looking forward to what you do with it. And yes, the wood was surprisingly nice. IIRC, it looks like at some point someone had a butt plate screwed onto it the plugged the holes..... my memory ain't what it used to be.
Right, that was your gun.
The main reason I like this gun is the stock was so nice.
I see a lot of these guns where the stock has been beat up or has cracks etc.
I don't think the stock had a butt plate as seen in the picture.
I see a lot of the 317/312 guns with the safety tab broken off for some reason.
Not the best design and best taken off and decock/cock the gun instead.
-
Since I was able to straighten out the original pump link it was time to replace the rivet.
Obviously I'm not the first person to work on this pump link.
The existing rivet was very hard so had to grind it out.
Best to use a mild steel that can be drilled and hammered.
Took an 8 penny nail and turned it on the lathe to .130" x .290".
Set it with a hammer and center punch.
Previously when pumped the arm would make a snapping sound due to the loose rivet.
Gun pumps nice and smooth now.
I guess you could say I nailed it?....LOL
-
Like I said.... memory ain't what it used to be.
-
Like I said.... memory ain't what it used to be.
My memory is so bad that I can't remember if I ever had a memory....LOL
-
Since I was able to straighten out the original pump link it was time to replace the rivet.
Obviously I'm not the first person to work on this pump link.
The existing rivet was very hard so had to grind it out.
Best to use a mild steel that can be drilled and hammered.
Took an 8 penny nail and turned it on the lathe to .130" x .290".
Set it with a hammer and center punch.
Previously when pumped the arm would make a snapping sound due to the loose rivet.
Gun pumps nice and smooth now.
I guess you could say I nailed it?....LOL
Ron you do nice work, wish I could do half of what you do. I bought a tootsie roll 342 on a whim, it holds air and the wood isn't bad, but it's dirty inside. I don't have the where with all to tear it down, I could make you a very sweet deal, would be nice to see it get your treatment and would be yours to do as you wish.
-
Ron , I once resealed a buddys 342 i believe.. anyway , that pivot area was also elongated, almost like it was meant to be that way.. It would click like a ratchet mid stroke.
-
Very nice work, Ron! I clocked my 312 2 months ago. Tim (Mac-1) did his 12 pump on it 15 years ago and thought you might want to see the results for comparison.
These stats were done on a Pact2 XP Infrared Chrony at 76 degrees F. 115 ft above Sea Level and 14.3 gr Crosman Superdomes. Looks like you may be on to something good!
BTW, I always keep 2 or 3 pumps in all my Bens and Dans when stored. dave
6 pumps 550 FPS
7 pumps 574.3
10 pumps 622.2
12 pumps 644.3
-
Very nice work, Ron! I clocked my 312 2 months ago. Tim (Mac-1) did his 12 pump on it 15 years ago and thought you might want to see the results for comparison.
These stats were done on a Pact2 XP Infrared Chrony at 76 degrees F. 115 ft above Sea Level and 14.3 gr Crosman Superdomes. Looks like you may be on to something good!
BTW, I always keep 2 or 3 pumps in all my Bens and Dans when stored. dave
6 pumps 550 FPS
7 pumps 574.3
10 pumps 622.2
12 pumps 644.3
Dave,
Thanks for the chrony results.
Hard to find performance stats on these old guns especially a Mac-1 tuned gun.
I think I can get about 650+ FPS with 8 pumps with a few more mods.
Trying to keep a balance between power vs pump effort.
-
Very nice work, Ron! I clocked my 312 2 months ago. Tim (Mac-1) did his 12 pump on it 15 years ago and thought you might want to see the results for comparison.
These stats were done on a Pact2 XP Infrared Chrony at 76 degrees F. 115 ft above Sea Level and 14.3 gr Crosman Superdomes. Looks like you may be on to something good!
BTW, I always keep 2 or 3 pumps in all my Bens and Dans when stored. dave
6 pumps 550 FPS
7 pumps 574.3
10 pumps 622.2
12 pumps 644.3
Dave,
Thanks for the chrony results.
Hard to find performance stats on these old guns especially a Mac-1 tuned gun.
I think I can get about 650+ FPS with 8 pumps with a few more mods.
Trying to keep a balance between power vs pump effort.
Ron, curious to see what yours does with 10 pumps. Keep up the good work....and keep us posted! dave
-
I made a new piston seal.
I noticed I couldn't adjust the pump arm to cam over and clear the breather hole.
This seal extends the piston so it touches the valve face and clears the breather hole at the top of the stroke.
The gun is harder to pump and the pump arm doesn't spring open much between pumps as before.
A definite sign that a good amount of dead air has been eliminated.
Pictured is the gun with the pump arm open after 7 pumps.
Previously the pump arm would spring open past 45 degrees.
-
Ran the gun over the chrony.
Wow, bumped up the power an average 80 FPS.
With 14.3 CPHPs Previous results in ( ).
03 pumps 498 (426) (402) FPS 07.87 (05.76) (05.13) FPE
05 pumps 615 (528) (473) FPS 12.01 (08.85) (07.10) FPE
07 pumps 685 (602) (524) FPS 14.90 (11.51) (08.72) FPE
Need to trim the check valve and replace the heavy spring in the valve.
That should get more volume.
-
those are some really good numbers.. any chance of pumping to 10 or is it just too hard ??
-
those are some really good numbers.. any chance of pumping to 10 or is it just too hard ??
I don't want to attempt 10 pumps until I max out the volume in the valve and change the springs.
It was retaining some air but I don't think that would make much difference.
In it's current configuration I think 8 pumps is the max.
I can always detune the gun by adjusting the piston for more head space.
I had to do that when I built this MF-DHP gun on the Green Forum
https://www.tapatalk.com/groups/thegreencrosmanforum/the-mf-dhp-will-rock-your-world-do-you-feel-lucky-t48451.html (https://www.tapatalk.com/groups/thegreencrosmanforum/the-mf-dhp-will-rock-your-world-do-you-feel-lucky-t48451.html)
-
am I wrong or do you need to have the felt washer behind the pistol to lubricate?
-
am I wrong or do you need to have the felt washer behind the pistol to lubricate?
Steve....With the stock steel piston a felt oiler should be used to minimize wear on the brass tube.
This piston is made from Delrin so no need for it, still has the oiler on the other end.
In the meantime took the gun apart to finish the mods on the valve.
Cut the Teflon check valve down and added some flutes to help it breath.
Using the original check spring with a blue Delrin spacer and a light SS valve spring.
Added a poly bumper to the back of the valve to prevent the hammer from impacting it.
Marked the valve seat with a sharpie and installed it with the port at 12:00 aligned with the barrel port.
Used a spare hammer spring that I cut 1 1/4" off so it's easy to cock.
Assembled the gun and it completely dumped 8 pumps.
Have to cock the gun before pumping due to the light valve spring.
The first few pumps are very easy until it starts to build pressure from 5-8 pumps.
-
Ran the gun over the chrony.
Made one pass with 10 pumps and an 8 pump pass with JSB Monsters.
With 14.3 CPHPs Previous results in ( ).
03 pumps 471 (498) (426) (402) FPS 07.04 (07.87) (05.76) (05.13) FPE
05 pumps 598 (615) (528) (473) FPS 11.01 (12.01) (08.85) (07.10) FPE
07 pumps 668 (685) (602) (524) FPS 14.17 (14.90) (11.51) (08.72) FPE
10 pumps 743 FPS 17.53 FPE (some RA)
With 25.4 JSB Monsters
08 pumps 545 FPS 16.75 FPE
With the added valve volume I was able to pump to 10 pumps but was hard.
Still made 25 FPS per pump from 7-10 pumps.
I will call this an 8 pump gun max, for everyday use 3-6 pumps.
-
Ran the gun over the chrony.
Made one pass with 10 pumps and an 8 pump pass with JSB Monsters.
With 14.3 CPHPs Previous results in ( ).
03 pumps 471 (498) (426) (402) FPS 07.04 (07.87) (05.76) (05.13) FPE
05 pumps 598 (615) (528) (473) FPS 11.01 (12.01) (08.85) (07.10) FPE
07 pumps 668 (685) (602) (524) FPS 14.17 (14.90) (11.51) (08.72) FPE
10 pumps 743 FPS 17.53 FPE (some RA)
With 25.4 JSB Monsters
08 pumps 545 FPS 16.75 FPE
With the added valve volume I was able to pump to 10 pumps but was hard.
Still made 25 FPS per pump from 7-10 pumps.
I will call this an 8 pump gun max, for everyday use 3-6 pumps.
Ron, those are incredible numbers! My Mac-1 Sheridan Blue streak clocked at 7.27.7 best I could get at 72 degrees, so I figure you're way in the ball park...and then some! BTW, I have to cock the Dan before pumping it up....coincidence...I think not! BTW, I talked to Tim Friday and told him what you're doing....and to check it out. I'll probably be in his shop Saturday. Your use of polymers and tooling in this appliction is impressive to say the least! dave
-
Ron , zippy 312 for sure. You may be able to pick up some free power by filling the annular groove in the valve seat exit. Some of those 312’s had a solid ( no groove) along with a non rotate provision.
Does a lead seal go on each side to seal it?
Interesting. I rebuilt the family 312 when I was 12 years old. I ordered a new valve seat . It was the type you have. The original was solid. I still remember that all these years later. My brother may still have it.
-
I believe per Tim recommended always cock before pumping unless you were just putting a couple pumps of air in for storage. My memory may be faulty.
-
Ron
You got a 1969 342 coming your way.
-
Ron , zippy 312 for sure. You may be able to pick up some free power by filling the annular groove in the valve seat exit. Some of those 312’s had a solid ( no groove) along with a non rotate provision.
Does a lead seal go on each side to seal it?
Interesting. I rebuilt the family 312 when I was 12 years old. I ordered a new valve seat . It was the type you have. The original was solid. I still remember that all these years later. My brother may still have it.
The valve body in this gun doesn't have the notch that aligns it with the valve seat.
I could make a poly ring to fill in the groove but aligning the ports in the gun would be difficult although not impossible.
I figured to just live with whatever loss there is.
I'd prefer to have the one hole valve seat type.
There was a lead seal on both ends of the valve seat but I put an o-ring in the front and no seal in the back.
Seems to get good power without it but I should install a seal to see if it makes a difference.
-
Ran the gun over the chrony.
Made one pass with 10 pumps and an 8 pump pass with JSB Monsters.
With 14.3 CPHPs Previous results in ( ).
03 pumps 471 (498) (426) (402) FPS 07.04 (07.87) (05.76) (05.13) FPE
05 pumps 598 (615) (528) (473) FPS 11.01 (12.01) (08.85) (07.10) FPE
07 pumps 668 (685) (602) (524) FPS 14.17 (14.90) (11.51) (08.72) FPE
10 pumps 743 FPS 17.53 FPE (some RA)
With 25.4 JSB Monsters
08 pumps 545 FPS 16.75 FPE
With the added valve volume I was able to pump to 10 pumps but was hard.
Still made 25 FPS per pump from 7-10 pumps.
I will call this an 8 pump gun max, for everyday use 3-6 pumps.
Ron, those are incredible numbers! My Mac-1 Sheridan Blue streak clocked at 7.27.7 best I could get at 72 degrees, so I figure you're way in the ball park...and then some! BTW, I have to cock the Dan before pumping it up....coincidence...I think not! BTW, I talked to Tim Friday and told him what you're doing....and to check it out. I'll probably be in his shop Saturday. Your use of polymers and tooling in this appliction is impressive to say the least! dave
Although the gun makes good power there are several things holding it back.
The pump link is not very sturdy, a steroid pump link would fix that.
The barrel is only about 19", a 24" barrel would be better.
The valve and barrel port are fixed and not accessible to enlarge.
There's a lot more power in that gun.
As an example:
The MF-DHP is a Disco tube based pumper with similar swept volume (although smaller) of this gun but made 960 FPS with 15 pumps.
It made 1034 FPS with 20 pumps and a 593 second shot with a little more valve volume.
https://www.tapatalk.com/groups/thegreencrosmanforum/the-mf-dhp-will-rock-your-world-do-you-feel-lucky-t48451-s10.html (https://www.tapatalk.com/groups/thegreencrosmanforum/the-mf-dhp-will-rock-your-world-do-you-feel-lucky-t48451-s10.html)
-
Ron
You got a 1969 342 coming your way.
Thanks, I'll keep an eye out for it.
-
Do you get air leakage around the breech/bolt? My 1959 312 had no O-ring there and was leaking air until Duy made a new bolt with O-ring.
-
Do you get air leakage around the breech/bolt? My 1959 312 had no O-ring there and was leaking air until Duy made a new bolt with O-ring.
No o-ring on this bolt, it's probably leaking some but it looks pretty tight.
I made a custom bolt for a 317 that had a worn breech so might make one for this gun.
It also had a nice power adjuster.
https://www.gatewaytoairguns.org/GTA/index.php?topic=160425.msg155789207#msg155789207 (https://www.gatewaytoairguns.org/GTA/index.php?topic=160425.msg155789207#msg155789207)
-
Ron , zippy 312 for sure. You may be able to pick up some free power by filling the annular groove in the valve seat exit. Some of those 312’s had a solid ( no groove) along with a non rotate provision.
Does a lead seal go on each side to seal it?
Interesting. I rebuilt the family 312 when I was 12 years old. I ordered a new valve seat . It was the type you have. The original was solid. I still remember that all these years later. My brother may still have it.
I had to
The valve body in this gun doesn't have the notch that aligns it with the valve seat.
I could make a poly ring to fill in the groove but aligning the ports in the gun would be difficult although not impossible.
I figured to just live with whatever loss there is.
I'd prefer to have the one hole valve seat type.
There was a lead seal on both ends of the valve seat but I put an o-ring in the front and no seal in the back.
Seems to get good power without it but I should install a seal to see if it makes a difference.
Had to try it.
Made a poly ring to fill in the groove around the valve seat.
First try I drilled a port @ .159" in the poly but the power actually dropped about 40 FPS.
I figured the port closed up when compressed in the gun.
Next, cut to the chase and cut some off the ring so there was some reserve space around the valve port.
Power came back up but basically the same as the stock setup.
Ran a limited chrony test.
With 14.3 CPHPs Previous results in ( ).
07 pumps 667 (668) FPS 14.12 (14.17)FPE
08 pumps 698 FPS 15.47 FPE
With 15.9 JSB Strattons
08 pumps 669 FPS 15.80 FPE
-
There's nothing better than actual scientific testing of results.
-
BTW.. I figured out which gun I was referring to earlier when I spoke of the butt plate being removed.... it was the Sheridan stock I sent to DeZ.... CRS !!
-
Made a new FT test piston with polyurethane o-ring seals.
Chrony tested almost identical to the previous poly seal piston.
Ran it with 70 and 90 duro seals.
With 14.3 CPHPs 70 duro seal
05 pumps 602 FPS 11.51 FPE
08 pumps 703 FPS 15.69 FPE
With 14.3 CPHPs 90 duro seal
05 pumps 600 FPS 11.43 FPE
08 pumps 702 FPS 15.65 FPE
-
Made a new FT test piston with polyurethane o-ring seals.
Chrony tested almost identical to the previous poly seal piston.
Ran it with 70 and 90 duro seals.
With 14.3 CPHPs 70 duro seal
05 pumps 602 FPS 11.51 FPE
08 pumps 703 FPS 15.69 FPE
With 14.3 CPHPs 90 duro seal
05 pumps 600 FPS 11.43 FPE
08 pumps 702 FPS 15.65 FPE
Very impressive! Will it dump all the air with 10 pumps? Just curious. dave
-
Made a new FT test piston with polyurethane o-ring seals.
Chrony tested almost identical to the previous poly seal piston.
Ran it with 70 and 90 duro seals.
With 14.3 CPHPs 70 duro seal
05 pumps 602 FPS 11.51 FPE
08 pumps 703 FPS 15.69 FPE
With 14.3 CPHPs 90 duro seal
05 pumps 600 FPS 11.43 FPE
08 pumps 702 FPS 15.65 FPE
Very impressive! Will it dump all the air with 10 pumps? Just curious. dave
It retains some air with 10 pumps but it's set up for 8 pumps.
Gets difficult to pump 8-10 pumps.
I'm going to make a new brass valve seat that will allow 10 pumps this weekend.
Similar to the one I made for the 317 restomod.
https://www.gatewaytoairguns.org/GTA/index.php?topic=160425.msg155784790#msg155784790 (https://www.gatewaytoairguns.org/GTA/index.php?topic=160425.msg155784790#msg155784790)
-
Made the new valve seat.
It has an 1/8" shaft, Delrin head, and .195" throat vs .215" on the stock seat..
Threaded the tail 1/4 x 28 vs 9/32 x 32 for the stock seat.
Opened up the port sideways since there is no alignment key, just have to position the seat at 12 o'clock mol.
Not sure if I'll put the seat in this gun or a 342 I just acquired.
-
A work of art! Can't wait to see how it performs.
-
Ordered a Mac-1 billet lever for this gun as well as the 342.
Should make the guns more solid when pumping and durable.
Need to make a larger wood pump arm also.
Like Hans and Franz said...."We just want to pump you up!....LOL
-
Ron, you're gonna make me wanna buy that gun back..... lol
-
Pulled the stock bolt out and made a brass replacement with an o-ring seal.
The original bolt is a flow through type but I like this style better.
-
Installed the brass bolt on the gun and tested.
With 14.3 CPHPs
08 pumps 708 FPS 15.91 FPE
With 15.9 JSBs
08 pumps 680 FPS 16.32 FPE
Swapped out the valve seat.
With 14.3 CPHPs
08 pumps 703 FPS 15.69 FPE
With 15.9 JSBs
10 pumps 740 FPS 19.33 FPE (full dump)
The brass bolt didn't seem to make a difference so the stock bolt was sealing good.
The stock bolt had almost .010" of clearance in the breech so made the new bolt plus .008", .288" vs .280".
No need for the little spring and ball anymore.
The ported valve seat and sealed bolt combo really came alive with 10 pumps and the heavier JSB pellets.
The barrel is only 19" so a longer barrel with larger ports would really help at the high end.
I'll run some more tests with heavy pellets after I install the Mac-1 billet pump arm.
An interesting note, the valve seat only has the front seal installed in all the tests as was done previously.
-
I bet that thing has a nice 'crack' to it when shot.
-
I bet that thing has a nice 'crack' to it when shot.
Has a nice crisp snap reminiscent of my hot rod V1 760 with the blow off valve.
-
Received the Mac-1 steroid pump levers today.
Super heavy duty and high quality, AAA+++.
Came with a bottle of "Secret Sauce".
Have a nice piece of walnut for the pump arm.
Turned it to 1.70" vs 1.20" of the original.
Here it is on the 342 gun still needing some final fitting and sanding.
-
Received the Mac-1 steroid pump levers today.
Super heavy duty and high quality, AAA+++.
Came with a bottle of "Secret Sauce".
Have a nice piece of walnut for the pump arm.
Turned it to 1.70" vs 1.20" of the original.
Here it is on the 342 gun still needing some final fitting and sanding.
Man, that handle looks like a 33 Louisville Slugger! ;) Some sanding , a little Walnut Minwax and some Tung Oil.....and you're good to go! dave
-
How do you like me now?....LOL
Sanded and stained the pump arm.
Matches this 342 stock really good so may have to make another for the 312.
-
Wow ! I'm liking that Ron.
-
This is just great Ron. I didn't know the steroid billet lever would fit the 312. Did you have to modify it and make a new endcap? Really nice job on the forearm.
-
This is just great Ron. I didn't know the steroid billet lever would fit the 312. Did you have to modify it and make a new endcap? Really nice job on the forearm.
The forearm and steroid link make the gun look like a serious pump shotgun.
Makes you want to grab it and rack that mutha!....LOL
The Mac-1 billet levers are a direct drop in.
They're pre-drilled so the tootsie can be transferred from the old link.
I'm going too use the original end cap for now but may make a new one.
The stock cap has a good deal of play and it is too short by about .435".
The pump arms are .250" thick and the slot in the cap is about .280".
Both my 312 and 342 have 2 roll pins that hold the front end together.
The fit of the pump link to the end cap makes a huge difference in how the gun pumps.
-
That really looks nice, Ron!
-
I might have missed it but, do you plan on anything for the metal finish?
-
I might have missed it but, do you plan on anything for the metal finish?
I like the old world patina on these guns so going to leave the metal as is.
Once it's gone there's no going back.
The bright brass look is nice but just not my style.
The new wood pump arm is going to take time for the finish to cure.
Attached a spare tootsie to the steroid lever for testing in the 312.
Got a little more power across the board.
With 14.3 CPHPs
05 pumps 613 FPS 11.93 FPE
08 pumps 721 FPS 16.50 FPE
10 pumps 775 FPS 19.07 FPE (full dump)
With 18.1 JSBs
08 pumps 657 FPS 17.35 FPE
-
Good call on leaving the metal as is... I'm a big patina fan as well.
-
With 14.3 CPHPs
05 pumps 613 FPS 11.93 FPE
08 pumps 721 FPS 16.50 FPE
10 pumps 775 FPS 19.07 FPE (full dump)
With 18.1 JSBs
08 pumps 657 FPS 17.35 FPE
Wow, those are some incredible numbers for a 312. You are the master!
-
With 14.3 CPHPs
05 pumps 613 FPS 11.93 FPE
08 pumps 721 FPS 16.50 FPE
10 pumps 775 FPS 19.07 FPE (full dump)
With 18.1 JSBs
08 pumps 657 FPS 17.35 FPE
Wow, those are some incredible numbers for a 312. You are the master!
Master skills not required.
A steroid 312/342 is well within reach.
The FT adjustable piston was responsible for the lions share of the gain.
The Delrin valve stem allowed full dump with 10 pumps.
As stated earlier, more valve volume, 24" barrel and larger ports would yield around 830 FPS 21.87 FPE.
-
With 14.3 CPHPs
05 pumps 613 FPS 11.93 FPE
08 pumps 721 FPS 16.50 FPE
10 pumps 775 FPS 19.07 FPE (full dump)
With 18.1 JSBs
08 pumps 657 FPS 17.35 FPE
Wow, those are some incredible numbers for a 312. You are the master!
Master skills not required.
A steroid 312/342 is well within reach.
The FT adjustable piston was responsible for the lions share of the gain.
The Delrin valve stem allowed full dump with 10 pumps.
As stated earlier, more valve volume, 24" barrel and larger ports would yield around 830 FPS 21.87 FPE.
Amazing work, Ron! The best I can get out my steroid Blue Steak with 12 pumps is 727.7 fps 14.3 gr. pellets. Good job! ;) dave
-
I made a new wood pump arm for this gun since the original matched the 342 better.
Modified it a little but basically the same look.
-
This has been an interesting thread. Who would have imagined 19 FPE from that little Benji. Well done