PP700 adventure started(Artemis PP700s-a)

[shultz]

Tried something a bit different for the pp700 today.  As many have noted with their pistols, I had some breech leakage.  To tighten the breech, it had been suggested that the valve could be removed and some material removed from its base to allow it to screw in further.  This has been done by at least one poster and works fine.  I decided to try a different route thinking that removing material from the valve base is irreversible and would to at least some minor degree reduce plenum volume.  I had some 0.4 mm thick metal that I used to make a shim to go between the breech block and the head of the valve.  A picture of the shim is below.  The square corners sit on top of the frame and locate it to prevent rotation but are probably not necessary.   I also made a slightly lighter valve spring to replace the stock spring inside the valve and drilled the transfer port hole on the breech face to match what I could measure at the base.  I leave the TP adjusting screw at the point where it doesn't restict the port and is as flush inside as possible and try to tune with regulator adjustment and hammer spring preload.  Cleaned everything up (quite a bit of metal shavings on the valve body), lubed original o-nngs, reassembled, and filled to 200 bar. 

Result-
No noticeable breech leak
Holding pressure after refilling to 200 bar
Velocity reached 885 to 895 fps range with 7.33 AA-wasn't shooting for group so I didn't check

Still a lot to figure out about fine tune on these things.  I noticed that once a stable velocity was reached that increasing (screwing in) the regulator would sometimes drop velocity but then increasing hammer spring preload would take velocity higher and above the original stable point.  The 885-895 range was the best I could attain today but I only had an hour or so to play around with it.

Nice mod. I took a slightly different approach with the same result. I shimmed out the breech plug by placing a small, thin .015 shim between the breech plug and the face of the breech it sits against. this shimmed the plug out to the block.

Making small, thin shims is SO much fun......

[Kid Shelleen]

Thank you so much for the reply John.  You're a life saver.  I thought I was going to have to try to drill and tap the breech with the "sleeve" or "breech plug" still in the breech which would probably involve actually drilling a little into the sleeve.  Removing the valve/breech block and taking the sleeve/barrel out the back sound so much easier (I hope).  Two questions:  What's the best way to degas the gun safely?  What size grub screws did you use and what was the distance from the back of the breech to where you drilled the hole?  Or did you put two screws in?

Thanks again for the information.  I was really hoping you would respond to this question since you have already taken this thing apart and tapped the breech to anchor the sleeve.  Shelleen

[Ozarkairgunner]

Got a stock built. This my second attempt, as the pistol's format is some what different than say a 1377 or a Disco.....




And this is the heart of the build. HERE is where your build precision skills are tested, and where the final quality of the build will be determined.


Still need to mount optics and create a cheek riser. An adjustable buttpad is required, as you'll never the ergonomics of it right enough, and you may need to adjust for the shooter

Love it man, can't wait to get my blank in and start working on it, how hard was it to get the correct inletting to fit properly

[shultz]

Thank you so much for the reply John.  You're a life saver.  I thought I was going to have to try to drill and tap the breech with the "sleeve" or "breech plug" still in the breech which would probably involve actually drilling a little into the sleeve.  Removing the valve/breech block and taking the sleeve/barrel out the back sound so much easier (I hope).  Two questions:  What's the best way to degas the gun safely?  What size grub screws did you use and what was the distance from the back of the breech to where you drilled the hole?  Or did you put two screws in?

Thanks again for the information.  I was really hoping you would respond to this question since you have already taken this thing apart and tapped the breech to anchor the sleeve.  Shelleen

Safest way to de gas is dry fire until the pressure gets low enough that you can, with a firm push on the hammer, dump the remaining air. I tried using the hand pump trick, I can't get it to work on either of my PP700's.
One other way to de gas is to loosen the air tube... yeah, this sounds dangerous and it probly is! I've had to do this a couple of times as my regulator would not allow air into the valve, so no dry firing the air out. Grab the air tube, turn it CCW(lefty loosy) MAKE SURE the entire air tube is turning away from the regulator! you don't want the air tube unscrewing from it's end. Look at the diagram, you'll see the air tube is 3 pieces. As the ENTIRE air tube backs off the end of the reg, the reg's O ring that seals it to the air tube will break seal and leak out all the air. I WOULD USE THIS METHOD AS A LAST RESORT!

Once de gased, you can remove the valve and breech block(they will pull off together once the valve is turned out far enough from the breech) now you can get the breech plug and barrel out thru the back.

I drilled and tapped mine for a 3mm grub, size doesn't matter really.... I just had a bunch of 3mm grubs so that's what I used. since the breech plug is flush with the end of the breech, I just measured from the end to the center of one of the flats on the breech plug. Put a piece of blue painters tape on the breech then marked that distance, keeping it centered in the opening. I drilled the hole nice and slow so I knew when the bit broke thru using my drill press. Tapped and de burred the hole.

I then screwed the barrel into the breech plug so it was nice and tight. push it into the breech, lined up one of the flats with the grub hole and snugged up the grub screw. Now, when you put the shroud back on, you can get the barrel nut end as tight as you want it! no need for it to be all that tight though. if you want to "free float" the breech plug like it was designed to, loosen the grub. I tried it both ways, didn't make a bit of difference accuracy wise so I chose to leave the grub snugged to the plug.

BTW, Rallyshark gets the honor for doing this mod, I just copied him

[bandg]

See my post above for a quick and easy way to degas the pistol.  Not my idea but I couldn't find the original post so thanks to that poster for the idea-works great.

[shultz]

See my post above for a quick and easy way to degas the pistol.  Not my idea but I couldn't find the original post so thanks to that poster for the idea-works great.

Bandg, I don't see where you mention degasing, am I looking at the wrong post? I'm curious how you did it...

[bandg]

Thought I had it in the above post.  Can't take credit for it but I don't remember who told me, maybe Rallyshark.  Take a plastic or rubber hammer and tap the back of the pistol hammer.  It takes a series of  taps over a couple of minutes but it does degas it pretty quickly.  Regulator flows out slowly so need to give it time to be sure all pressure is out.

[Rallyshark]

Tried something a bit different for the pp700 today.  As many have noted with their pistols, I had some breech leakage.  To tighten the breech, it had been suggested that the valve could be removed and some material removed from its base to allow it to screw in further.  This has been done by at least one poster and works fine.  I decided to try a different route thinking that removing material from the valve base is irreversible and would to at least some minor degree reduce plenum volume.  I had some 0.4 mm thick metal that I used to make a shim to go between the breech block and the head of the valve.  A picture of the shim is below.  The square corners sit on top of the frame and locate it to prevent rotation but are probably not necessary.   I also made a slightly lighter valve spring to replace the stock spring inside the valve and drilled the transfer port hole on the breech face to match what I could measure at the base.  I leave the TP adjusting screw at the point where it doesn't restict the port and is as flush inside as possible and try to tune with regulator adjustment and hammer spring preload.  Cleaned everything up (quite a bit of metal shavings on the valve body), lubed original o-nngs, reassembled, and filled to 200 bar. 

Result-
No noticeable breech leak
Holding pressure after refilling to 200 bar
Velocity reached 885 to 895 fps range with 7.33 AA-wasn't shooting for group so I didn't check

Still a lot to figure out about fine tune on these things.  I noticed that once a stable velocity was reached that increasing (screwing in) the regulator would sometimes drop velocity but then increasing hammer spring preload would take velocity higher and above the original stable point.  The 885-895 range was the best I could attain today but I only had an hour or so to play around with it.

Actually, taking material off the base of the valve can be "reversed", since you can simply screw it back out to the original position.  The seals that keep the air aren't affected.  I think it only took about 1/4 more of a turn on the valve to get mine seated better while lining up the remaining hole on the valve after I modded it.  Any loss in plenum size would be insignificant, since I only had to take a very small amount off to get that extra 1/4 turn.  I do like your solution as well.  I've also seen someone else do that, but with a round shim.  I think yours if probably more stable.  Nice job on that! Your end result is exactly the same, even if the method is different.  After all, it is the end result that matters the most  

Did you happen to open up that valve spring retaining nut while you had it out?  I was really wanting someone to try just doing that to see the results with no other mods out of curiosity.   I'm way too far past that to test it on mine,lol.

It makes perfect sense that your velocity would drop a bit with an increase reg pressure, and not changing the hammer spring.  There is more pressure holding the valve shut, so it takes more hammer strike to open it. 

Dan, there is one great thing I see about that stock you made.  You can mount a picatinny rail on that "forearm" grip!  I think a nice little green or red LED light on there would make for a heck of nice ratting or night pesting gun!  I bet that little stock if comfy to shoulder and shoot as well!

[dan_house]

, how hard was it to get the correct inletting to fit properly

I didnt inlet it. The paper pattern shown is the center of 3 peices. outer two are 1/2 inch thick, center one is 3/4 (although be prepared for it to just undersized from that, and make it a tight fit). carfeuly cut the wood out and glue on the other two side. Instant inletting. BUT!!!! If that channel isnt darner enar perfect, you'll spend some time fitting the gun in the slot. Biggest tip I can give is to spent MUCH time fitting this to action, and when it fits well, then mark and drill the bolt hole in that piece

Apparently I didnt take a pic of the pattern for the outer peices. Its the same profile, but no action inletting and its much wider/taller on the part under the air tube.

More pics I guess

[Ozarkairgunner]

Right on, the inletting is really the only part I'm really worried about on mine at the moment, I want mine to be a solid 1 piece stock out of laminated wood, but let's not get to far off topic, that'll be better saved for another gate when my blank makes it in.

[Bob Pratl]

Thought I had it in the above post.  Can't take credit for it but I don't remember who told me, maybe Rallyshark.  Take a plastic or rubber hammer and tap the back of the pistol hammer.  It takes a series of  taps over a couple of minutes but it does degas it pretty quickly.  Regulator flows out slowly so need to give it time to be sure all pressure is out.

In trying to isolate and repair a small leak I had to fill and degas my MK II many many times and after the third go around I found it easier to degas it by just pushing the hammer hard, not banging it, against the edge of my work bench and it would degas out the barrel in two seconds. It takes a lot less effort than I thought to press the hammer in and hold it. Bob

[dan_house]

I want mine to be a solid 1 piece stock out of laminated wood,

YEs that would be way cool.... Just take a lot of measurement, draw it out a lot, then redraw it again... Thinkit thru and it shouldnt be that hard....

[Ozarkairgunner]

I want mine to be a solid 1 piece stock out of laminated wood,

YEs that would be way cool.... Just take a lot of measurement, draw it out a lot, then redraw it again... Thinkit thru and it shouldnt be that hard....

Just a little bit at a time nice and easy. I checked my status and it's showing to be here around the 20th, my crony should be in by then too so while I'm working on the stock I'm going to disassemble my pistol, rework the regulator Bellevue stack, and do the hatsan JB weld valve mod that Donny has done as well. Between work, a toddler, and a 4 month old it'll be a long process, but I'll post pics as I go. Fingers crossed that everything goes smoothly on the first attempt

[bandg]

I remember now someone mentioning opening the valve spring retaining screw and I had planned to do so but forgot and didn't do it so no idea there.  There is room to drill it larger since the base is pretty wide and the stock spring is conical and I spent time shaping the one I made to match as closely as possible.  I'll try that if I take it down again but it seems to be free of leaks and getting 885 to 895 with 7.33 gr. pellets so I'm pretty satisfied for now.  It did seem like the o-rings both at the base of the valve (single black) and at the breech block position (dual brown) were not as thick as they could be, seems like they were pretty loose in the grooves and could be very easily pressed to the top of the groove and with almost no resistance detectable when reassembling.  I spent some time last night looking for comparable o-ring sizes and plan to order some to see if a slightly larger o-ring might fit at those locations if I do disassemble again.  As to the degassing, I don't think the light tapping needed could damage anything considering how hard the hammer strikes and I certainly wouldn't call it banging on anything as it really takes very little effort to make it work.  But if the steady pressure works that's good to know too, thanks.

[Kid Shelleen]

Is the set screw hole for the breech/barrel sleeve drilled in the top of the breech or the side of the breech?  Maybe it was mentioned but I missed it.

I got the gun apart to tap the breech for the set screw but realized I didn’t know where to drill the breech… from the top of the breech or from the side (left or right side?).  The sleeve is about 12mm long and the flat starts about 4mm from the rear of the sleeve and the flat is about 5.5 mm long, ending about 10mm from the rear of the sleeve .  That means the set screw should make contact in the middle of the flat at about 7mm from the rear of the breech.  If the set screw hole is drilled from the top of the breech, it would have to be drilled almost touching the rear of the rear sight and would actually have to cut part of the dovetail base of the rear sight and into part of the dovetail in the breech.  I suppose the rear sight could be removed, the hole drilled and tapped and a short grub screw inserted so that it rested below the surface of the dovetail so the rear sight could be put back on.  It seems to be easier to drill the side of the breech.

My thanks to Rallyshark, Schultz and Bandg for the information on removing the breech/barrel sleeve and taping the breech for a set screw to keep the sleeve from rotating inside the breech.  Since the sleeve has two flats on it, it almost appears as though the original design called for a set screw on the breech.  I don’t understand why the manufacturer didn’t follow through with that design.  Leaving that sleeve in the breech without some means of securing it when the barrel in threaded in, is just asking for trouble.  My sleeve is so loose it easily rotates inside the breech.

[bandg]

If I recall the pictures I've seen show it drilled on the frame side, the left as you hold the pistol if I remember correctly.  I haven't done it myself so verify before you do it

[Rallyshark]

I tapped mine on the right and left side, so there is a set screw on each flat side.  It is in the same position on each side.  I'm sure one probably would have been sufficient, as far as keeping the part in place goes.  I attached a picture of it.. I've also seen some of the guys across the pond tap it from the top at the rear to hold the collar, and one at the front on the barrel itself.  I really think it is just a matter of personal preference, since at least one at the rear to hold that collar is the most important  

[Wayne52]

Donny I never did that mod, it didn't seem to need it, when I installed the Rocker LDC & adapter it snugged up nicely.

[Rallyshark]

Donny I never did that mod, it didn't seem to need it, when I installed the Rocker LDC & adapter it snugged up nicely.

I think you got luckier than some of us did on that.  I know I've seen some that had an experience like yours, and some that didn't.  I think it must depend on how well that collar fits in the breech on each individual gun maybe?  I needed to put the set screws on mine, or it wasn't going to tighten down.  I've seen a lot of the gents across the pond that had to do it as well.  It just depends on the machining on the gun.  Obviously, not having to install set screws would be the preferred route to go.  It would have been easy for them to make the collar completely flat on once side, and a flat side in the breech so it couldn't turn.  I suppose that is a bit more complicated than just making a round hole in the manufacturing process 

[Kid Shelleen]

Thanks Donny & Bandg,  Just what I needed to know.  I'm going to try to drill mine tomorrow.