GTA
All Springer/NP/PCP Air Gun Discussion General => Machine Shop Talk & AG Parts Machining => Show Off Your Air Guns With Mods (SHOW and TELL) => Topic started by: BigBird on July 25, 2019, 02:22:29 AM
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I modified my CO2 J.C. Higgins 22 (yes I know it is a classic - this was a $15 non-working parts gun) to shoot .308 (PB) using an old take off barrel in a unibody fashion where the breech is integrated into the barrel (barr-eech). The barrel is from a 30-06 Remington 700 and has about 17" of barrel and the rest is breech (turned down to ~ 3/4".
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=6665)
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=6663)
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=6664)
The reason I chose this gun to start was 1. It didnt work, 2. It has a longer breech, 3. There arent any holes forward of the valve (Crosman), and 4. It has a great trigger.
I am using pellets (currently undersized)
I was just trying to make a breech for the 22 barrel but it worked with the barrel so I didnt cut it off.
This is an ongoing project to learn about Lathe work and HPA (I know it looks like the spawn of snaggle-toothed Bubba). Ive tried to use "some" of what Ive learned here. I "hope" to make this into a 308 or 357 for medium game and would like to get power over shot count. For a hunting gun, 3 shots are ok if they can take down a coyote.
I fabricated the
Barrel/breech
Delrin spacer
Bolt - 303 SS
Bolt handle - 304 SS
Fill end - 1020 tool steel
Valve - 303 SS
Poppet - O1 & Delrin
Hammer - 303 SS
Transfer Port -303 SS
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=6657)
Valve
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=6658)
Valve
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=6659)
Valve
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=6660)
Couple minor faux pauxs on the valve. I forgot this seals in a larger diameter step down portion of the front of the tube, which can only be done really like the original screw on (or at least for me). I had an oring up front then used the location further back. It seems to work well. The rear half of the valve spring-anchor screws in 2 ways, one in middle to remove the poppet/spring and the outer to tighten down on the oring to seal the valve. I can remove the poppet without unscrewing the sealing portion (great for testing). I replaced the thin spring on the poppet from picture.
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=6662)
At this stage it holds air and shoots a declining string from 759, 646, 563 FPS on a meager but "safe" fill of 1400 PSI. I won't go higher due to the CO2 designed fill end.. I used 44.75 gr pellets for 57 FPE (78 joules).
Fill end
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=6667)
Fill end 2
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=6669)
End cap before
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=6668)
I would however like to add a tube extension for more air capacity. I will pin the valve with 2- 8-32 low head SHCS. I would use the thicker portion of the tube to anchor pins for the extension and test with my hydraulic pump. I could also use a bottle reg 1300-1500 PSI but feel that may be too restrictive for plenum (?).
The valve is designed to span all screw holes for strength and simplicity. Before there was a separate ring inside that "secured" the front trigger screw and breech screw.
The. 5/16 OD, 1/4 ID TP goes from the bore of the valve to well inside the barr-eech. I dont have any sealant it just presses up against the sides of each and top of barrel port.
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=6645)
Hammer is attached to the spring guide/handle and uses a 1/2 a spring from my Mauser firing pin spring. It is pretty heavy altogether but seems to have good lock time/force.
At some point I am planning to put a different breech (a QB 79 - thnx Mudbugmitch) and a 2 groove take off barrel from my "US Model of 1917 Enfield Eddystone Sporterized from Military Mongrel" (PB fodder - check youtube). It will give me 24" (17" now) and may look a little more normal.
Its not pretty but I think it works and is safer than original. I'm asking about more air tube and would like to get suggestions.
Thanks,
Dan
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Great effort! Following the old Crosman integral breech and barrel design makes for a rigid platform. Pictures always complement a project. Well done!
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awesome results ! i guess the next challenge would be to make a new main tube for it to handle even more pressure.. Id be curious to see the numbers on bulk co2 also.. nice job
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awesome results ! i guess the next challenge would be to make a new main tube for it to handle even more pressure.. Id be curious to see the numbers on bulk co2 also.. nice job
Thanks. A new tube would make more sense than adding an extension tube onto the existing tube. For an extension there would have to be a lot of metal taking up space for the connection and at least 4 pins (haven't done math on it). I'm not even sure it could be done. I have safety concerns too a it opens up room for error and creating a powerful/deadly rocket... For a new tube the only issue is my lathe is 7×14 with a 22mm spindle bore. I think I'd be using my steady rest and a file or farm it out. That discussion however might be better for the machining forum.
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Thread moved to machine shop show & tell.
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Id be curious to see the numbers on bulk co2 also.. nice job
X2 :D
Al
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awesome results ! i guess the next challenge would be to make a new main tube for it to handle even more pressure.. Id be curious to see the numbers on bulk co2 also.. nice job
Thanks. A new tube would make more sense than adding an extension tube onto the existing tube. For an extension there would have to be a lot of metal taking up space for the connection and at least 4 pins (haven't done math on it). I'm not even sure it could be done. I have safety concerns too a it opens up room for error and creating a powerful/deadly rocket... For a new tube the only issue is my lathe is 7×14 with a 22mm spindle bore. I think I'd be using my steady rest and a file or farm it out. That discussion however might be better for the machining forum.
one of these days a motivated guy with a cnc lathe will roll out a a new spindle upgrade for the 7 inch lathes.. the machines would be soo much better with a 1.0 inch spindle bore it would be crazy..The issue there is the new spindle would not only need new bearings , it would also need a new drivetrain and possibly new hi-low gears on most models.
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Anyone know why these pictures are not showing up? It says "Sorry, you are not allowed to view this file. Make sure you are connected to the server."
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They are showing for me. Try a different browser and also make sur in the security tab of the browser settings you allow for viewing of all content, secure and not secure.
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I also see the pictures.
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Very nice work, well done!
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one of these days a motivated guy with a cnc lathe will roll out a a new spindle upgrade for the 7 inch lathes.. the machines would be soo much better with a 1.0 inch spindle bore it would be crazy..The issue there is the new spindle would not only need new bearings , it would also need a new drivetrain and possibly new hi-low gears on most models.
Hmph. There's easier ways to turn a 1" tube then that in the 7" lathes.
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one of these days a motivated guy with a cnc lathe will roll out a a new spindle upgrade for the 7 inch lathes.. the machines would be soo much better with a 1.0 inch spindle bore it would be crazy..The issue there is the new spindle would not only need new bearings , it would also need a new drivetrain and possibly new hi-low gears on most models.
Hmph. There's easier ways to turn a 1" tube then that in the 7" lathes.
still not as easy as having the spindle bore to do it though..
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still not as easy as having the spindle bore to do it though..
Maybe not but the Pyramids were built without modern cranes.
Necessity is the tool of invention! You can invent or pay through the nose to those that will.
;D
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still not as easy as having the spindle bore to do it though..
Maybe not but the Pyramids were built without modern cranes.
Necessity is the tool of invention! You can invent or pay through the nose to those that will.
;D
when i had the 7 by 12 i actually bored the spindle a few thou over/ used the steady rest pretty often also.. but agreed a lot can be done on the machines as they are
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still not as easy as having the spindle bore to do it though..
Maybe not but the Pyramids were built without modern cranes.
Necessity is the tool of invention! You can invent or pay through the nose to those that will.
;D
I thought you were talking about an add on device. I thought about securing the lathe and putting my drill press on the end where a future 1-1/8x.095 tube might be. I think minimal end work would be needed for a pinned fill cap.
I'm still not finished with my 1" 45 cal barrel for the next project. It happens to be 1" at the breech and I was reducing the muzzle end to 3/4 using my steady rest. It was fluted and the bits don't like cutting over that. I still have some work left on it for both ends and starting on the breech side. Then I thought about making a barrel spinner somehow to finish it off. My lathe motor crapped out on me and I'm working with less RPMs on a replacement. Not ideal even for smaller diameter.
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=6676)
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still not as easy as having the spindle bore to do it though..
Maybe not but the Pyramids were built without modern cranes.
Necessity is the tool of invention! You can invent or pay through the nose to those that will.
;D
I thought you were talking about an add on device. I thought about securing the lathe and putting my drill press on the end where a future 1-1/8x.095 tube might be. I think minimal end work would be needed for a pinned fill cap.
I'm still not finished with my 1" 45 cal barrel for the next project. It happens to be 1" at the breech and I was reducing the muzzle end to 3/4 using my steady rest. It was fluted and the bits don't like cutting over that. I still have some work left on it for both ends and starting on the breech side. Then I thought about making a barrel spinner somehow to finish it off. My lathe motor crapped out on me and I'm working with less RPMs on a replacement. Not ideal even for smaller diameter.
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=6676)
Replying to myself...
This other 45 cal. build will be over a year (as most of them are due to work, etc.) so hard to post progress here.
So what are your thoughts on 1020 internals for 15/16" ID? I think it is forboden but I made another valve with it and it is technically stronger than 3600 brass. I like 303 but it is difficult to work/drill into due to work hardening. I've got 2 - 1.25" × 36" 303 rods but they are more difficult to cut into (used steady rest).
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referring to valve material ?? generally speaking people go overkill for valve materials .. aluminum 6061 or brass work fine for valve construction , they just need to be properly pinned like any other material. 7075 and 2024 are also good options.. As for the tube , that needs to be critiqued way more .. dom513, alum 2024 , 7075, a few variants of stainless , all depends on diameter and material , oring placement , thread depth , wall thickness at thread root. etc etc
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referring to valve material ?? generally speaking people go overkill for valve materials .. aluminum 6061 or brass work fine for valve construction , they just need to be properly pinned like any other material. 7075 and 2024 are also good options.. As for the tube , that needs to be critiqued way more .. dom513, alum 2024 , 7075, a few variants of stainless , all depends on diameter and material , oring placement , thread depth , wall thickness at thread root. etc etc
Yeah I was thinking of valve and ends 15/16" diameter. I have 1" 6061 not being used that I can repurpose. I think I'd use caution using it for a threaded fill end though. Just me...
Tube would be DOM 1026 - a513.
Thanks
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referring to valve material ?? generally speaking people go overkill for valve materials .. aluminum 6061 or brass work fine for valve construction , they just need to be properly pinned like any other material. 7075 and 2024 are also good options.. As for the tube , that needs to be critiqued way more .. dom513, alum 2024 , 7075, a few variants of stainless , all depends on diameter and material , oring placement , thread depth , wall thickness at thread root. etc etc
Yeah I was thinking of valve and ends 15/16" diameter. I have 1" 6061 not being used that I can repurpose. I think I'd use caution using it for a threaded fill end though. Just me...
Tube would be DOM 1026 - a513.
Thanks
ive used it for threaded pressure end.. Even though its fully capable , i thread twice the length i would with steel just to be on the safe side.( really to cure my own anxiety ). So a recent build had a full inch of m17-1.0 threads into the tube ( 25.4 turns roughly)
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Okay if people over-engineered internals so cap and cap and valve how about annealed A36.
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=6684)
Specifications say it is better strength than brass. I've always wanted to use his big bolts for something.
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is this a trick picture?? whats the bolt come from?? thats awesome .. or maybe the chuck is really small?
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is this a trick picture?? whats the bolt come from?? thats awesome .. or maybe the chuck is really small?
I get some very large cheap bolts locally. The shank on this one is 1.10". It machines pretty easily after the zinc coating is take off. I stuck a few in the grill after the foid was out. Not sure how that affects the metal other than it is easier to cut. A36 is metal from scrap. I've had some A36 cement nails that I couldnt drill through and others that were easy to drill through.
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Took off the delrin spacer and cut down the transfer port bushing (still need to cut down the rear breech screw though!) Took it and a couple other guns out hunting/sighting in today and it works good. Takes 35 pumps from empty to full and I take two and pump again. No chrono in this back woods. I really need to get to a range for that (can't shoot this in the back yard).
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=6798)
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An opossum (white hand) decided to play dead right in front of our makeshift target (bunch of newspaper)(black hand). We didn't shoot him but flung the lead right over him like it was going out of style.
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=6799)
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I have been working on this basically to for more experience. Mainly learning what not to do (don't start with a screw on oring/spring retainer). I will eventually go through the QB78 valve mods. Next being fixed oring, rear spring on poppet if that is possible.
I made my own 7/8 x .065 1020 DOM tube, pinned it (should be 1.5 center screw head calculation), tested it to 8000 PSI, changed the valve around, added side cocking (spring guide screw still goes out the back). It is the same 17" barrel with a 3/4 x .083, 5/8-24 threaded extension to protect the nipple (live and learn) and bling on the front of the barrel (a beauty ring).
I was getting close to 900 fps with 44.75 gr (undersized) airgun pellets so I cut the forward section off some 200 gr hard cast lead bullets I had available. They are about 100 gr and rifling engraves them (finally something .308!).
I haven't done a whole lot of testing because I don't have access to a real range (saving bullets for inaccuracy testing) and I burried a 100 gr bullet in the wall behind my downstairs "trap". I have since reinforced it with rubber mulch!
The string looks promising for a coyote gun but will this speed allow me to shoot accurately (stabilize but not overly stable)? I don't know but my inkling is I need a littlle more power/bullet length.
2500 PSI start
606 fps
667 fps (97 FPE)
653 fps
? Ending psi (didn't have time, was ok with these).
I have the 17" PB barrel (30-06 so 1:10 twist) right now on it. So my question is, what .308 airgun bullets should I be looking at for estimated stable flight. Hunters supply has 79 gr and 111 gr. I know Accurate molds has a lot of choices and NSA has some. Or maybe 1:10 is a lost cause? It is fun though.
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=7441)
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=7442)
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I have been working on this basically to for more experience. Mainly learning what not to do (don't start with a screw on oring/spring retainer). I will eventually go through the QB78 valve mods. Next being fixed oring, rear spring on poppet if that is possible.
I made my own 7/8 x .065 1020 DOM tube, pinned it (should be 1.5 center screw head calculation), tested it to 8000 PSI, changed the valve around, added side cocking (spring guide screw still goes out the back). It is the same 17" barrel with a 3/4 x .083, 5/8-24 threaded extension to protect the nipple (live and learn) and bling on the front of the barrel (a beauty ring).
I was getting close to 900 fps with 44.75 gr (undersized) airgun pellets so I cut the forward section off some 200 gr hard cast lead bullets I had available. They are about 100 gr and rifling engraves them (finally something .308!).
I haven't done a whole lot of testing because I don't have access to a real range (saving bullets for inaccuracy testing) and I burried a 100 gr bullet in the wall behind my downstairs "trap". I have since reinforced it with rubber mulch!
The string looks promising for a coyote gun but will this speed allow me to shoot accurately (stabilize but not overly stable)? I don't know but my inkling is I need a littlle more power/bullet length.
2500 PSI start
606 fps
667 fps (97 FPE)
653 fps
? Ending psi (didn't have time, was ok with these).
I have the 17" PB barrel (30-06 so 1:10 twist) right now on it. So my question is, what .308 airgun bullets should I be looking at for estimated stable flight. Hunters supply has 79 gr and 111 gr. I know Accurate molds has a lot of choices and NSA has some. Or maybe 1:10 is a lost cause? It is fun though.
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=7441)
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=7442)
Ok I realize this is not as serious a build but maybe use it for what not to do.... There is learning either way. Maybe most of the learning on my part.
Must make a retraction! These forward sections are NOT .308 as I was thinking. Duh. Obviously the land-riding section of the bullet. So I was still at the same size as the AG pellet! I tried the rear section and couldn't close the bolt. I had thought I throated the barrel in making it originally but was wrong.
Couple issues with the quick and dirty method I used. You should've already decided this wasn't the method for you long ago (my defense: first project and I wasnt going for a barrelled action). I originally drilled the bolt "runway" with a 5/16 bit to the length of the bit minus chuck jaws. This gave me a bore sized bolt. Takeaway: the oring rides on the runway.
Fix: I could have got a longer drill bit but it would leave a 60° transition to lands so I made a makeshift throater with 5/16 O1 tool steel with a smoother transition to lands. I hardened it in oil and set in the toaster oven right above the elements for 2 hours. Came out blue on the rear so hopefully normalized on the front.
Since O1 tool steel is exactly .312 and my drill bit hole was closer to .309, I had to open it to the size of a larger bolt I wanted to use for the...bolt. Now the throater goes in and cuts. I have to smooth out the transition from bolt to .312 and make a new bolt but I'm more confident I can get back to "wow I can't believe this thing works!" (at 10 yds).
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=7454)
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=7455)
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looking good.. what size poppet are you using ?
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looking good.. what size poppet are you using ?
I'm going to have to check the poppet size. It is minimal. The valve throat is 5/16" and I think the TP is 1/4". The new hollow bolt probe will probably be about 15/64" but that is a downgrade from the previous that was .245 and a little too thin.
I'm almost done with the bolt. Didn't have my phone to take pics (might break camera though). It needs the transfer port hole, an oring and the rear cut off. I'm pretty pleased because it didn't retain any drills or taps in the handle threading process (++) and uses the old bolt-bolt handle. These bolts came cheap but they work a little better than mild tool steel for the strength areas of bolt handle (10-32) threads and the bolt probe.
With the bolt it has nice tight lockup and I can almost "chamber" a 200 gr hard cast test bullet. Off by about 1/8"-5/32" but the throat (leade) accepts .432" of full bore diameter maybe a little more considering the front of the probe is just in front of the TP hole. I could, but I wouldn't, reduce it that much until I can figure out which bullets are least inaccurate. I don't think I could shoot longer bullets anyway. It looks like it would be great for up to the Accuate Bullet Mold Bullet design #31-110A
http://www.accuratemolds.com/bullet_detail.php?bullet=31-110A-D.png (http://www.accuratemolds.com/bullet_detail.php?bullet=31-110A-D.png)
Learned alot more about what not to do but I don't have time to post those details.
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After throating and a new bolt I shot four shots with the front section and first driving band of the 200 gr hard cast .308 boolits. I think the driving band is bore size.
I figured they were about 142.1875 gr each based on weighing 4 on a postal meter.
The string surprised me and I think based on the declining I can go to 2800 or maybe 3000 psi, which would be great. I don't know how soft lead airgun bullets would affect this shot string but there WILL be more contact with the grooves due to the 2 or 3 more driving bands.
142 gr @ 591 = 110 fpe
142 gr @ 589 = 109 fpe
142 gr @ 559 = 99 fpe
142 gr @ 513 = 83 fpe
- beefier bolt
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=7456)
Front bolt. I left the hollow probe opening 7/32". I think it is ok. The air doesn't see much of the bolt as it turns the corner. The hole in the bolt is so big and far forward there isn't much left of the front bolt infront of the hole.
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=7457)
142 gr Boolit - here is what I used for testing. It is what I have on hand.
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=7458)
First of four shots using142gr boolit starting at 2500 psi
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=7459)
Remaining air - not sure how this measures up. I think there were about 20 hand pumps for each shot.
(https://www.gatewaytoairguns.org/GTA/MGalleryItem.php?id=7460)
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thats some serious power man ! wwonder how theyd shoot at that speed
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I was able to get out and finally sight my bigger bore air rifles in that I can't shoot in the back yard. I took the .58 caliber and this .30 caliber. I had laser bore sighted both and shot the .30 caliber in the basement so it was a 2 shot sight in for botg guns (very unusual for me). This was only about 35 yds but they both shot really well. I was using the cut down hard cast bullets so whenever I get some proper airgun bullets or get a mold to cast some it should shoot even better.
Here is the YouTube of a couple shots:
https://youtu.be/aCqyPrux3t0 (https://youtu.be/aCqyPrux3t0)
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nice .. how are you getting flow past the bolt , it looks like it full bore ... is it hollowed somewhere?
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It is a hollow bolt probe about 7/32". So not full bore porting but the transfer port is 1/4" and the bolt probe hole is only about 1/16" away from the end of the probe so the restriction is not very restrictive I guess. I could hollow out the probe a little more but I don't think I'd get much increase.
It still needs some other work like a better cocking handle. Its not quite as heavy cocking as it looks in the video but a bigger handle would be better. Also getting rid of the rear bolt sticking out which was a holdover from a previous cocking method.
It may look cobbled but it was fun to try to make things work that weren't really supposed to. Kind of like a junk yard wars gun. I need to learn how to make my own trigger as that seems like the stopping point of some other projects. I have a .429 in the works. Not sure why there arent any "44 magnum" airguns? We are missing the "go ahead make my day" deer...gun.
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Pretty danged cool if you ask me !!!
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Thanks Wayne! I'm having fun working on them. Now I need something I can deer hunt with. I have a ".46" caliber in the works but I am taking a little more time on that one.
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Ahem... Almost forgot. Thanks for help GTA! I wouldn't have known how to if I didn't read about it. I played a lot with Crosman legos too.