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Old 01-06-2007, 07:07 AM   #1
XHardrock
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Default 7.62X25 coversion ?

I'm working on a 7.62x25 AK conversion and need to know what works best for feed geometry using a PPS mag and barrel.
Should I angle the mag so the rounds are angled up mostly avoiding the feed ramp, or run the mag lips parallel with the rails allowing the ramp to direct the round?
Thanks
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Old 01-06-2007, 09:37 AM   #2
azhonkey
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Quote:
Originally Posted by XHardrock
I'm working on a 7.62x25 AK conversion and need to know what works best for feed geometry using a PPS mag and barrel.
Should I angle the mag so the rounds are angled up mostly avoiding the feed ramp, or run the mag lips parallel with the rails allowing the ramp to direct the round?
Thanks
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Old 01-06-2007, 12:04 PM   #3
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XHardRock
My mag wells for the PPSH 41 drum and stick set at about 4.5 to 5 degrees.
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Old 01-06-2007, 02:37 PM   #4
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The pic helps alot, and looks good too.
Seems I am dead on, which is the same angle it was located on the PPSH.

Thanks guys.
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Old 01-06-2007, 03:39 PM   #5
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I think azhonkey has more of an angle on his. That is totally kickbutt by the way azhonkey . I had the mag lips up to rail level on mine. I found to much of an angle and the bullet can jam. I was getting alot of rounds hitting edge on and causing the bullet heads to be pushed in. The feed ramp was a big deal on my build. If I had to do it again I would have heated and bend my ak-74 feed ramp down more.
http://www.akfiles.com/forums/showthread.php?t=15078
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Old 01-06-2007, 05:17 PM   #6
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Quote:
Originally Posted by camoguy
I think azhonkey has more of an angle on his. That is totally kickbutt by the way azhonkey . I had the mag lips up to rail level on mine. I found to much of an angle and the bullet can jam. I was getting alot of rounds hitting edge on and causing the bullet heads to be pushed in. The feed ramp was a big deal on my build. If I had to do it again I would have heated and bend my ak-74 feed ramp down more.
http://www.akfiles.com/forums/showthread.php?t=15078
camoguy
your project is starting to take shape,looks real good.for what it's worth mine started out as gas operated.wouldn't run with 6 inch barrel,it would unlock the bolt but wouldn't cock the hammer so converted to blowback.that worked fine.talked to RODGER (same member on this thread) he's building a 9mm gas operated project,suggested i add more barrel length and lightin up the hammer spring.to make a long story short i added 5 inch barrel extenion and removed one wire wrap on the hammer spring,down to two wires,made a big differance.so i'am back to gas operated,hope to give it a test run in a week or so.
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Old 01-06-2007, 06:58 PM   #7
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Great info gents, and fine looking builds.

I am attempting using the ppsh 43 barrel and hope it will be gas operated.
At this stage the gas block will be 4" from the end of the barrel and I hope that leaves enough gas to operate. The gas piston will be very short.
While I enjoy building, this is getting to be more involved than I expected. Definately a learning experience.

Thanks again
HR
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Old 01-06-2007, 07:24 PM   #8
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XHardrock - I can't see your build cycling well with that short of a barrel and a gas block that close..if you make it gas operated. You don't get much duration. In any event you will need to lessen the mass of the bolt/carrier,piston, and spring. Maybe one or more of the above mentioned peices will have to be modified. Can you give us a better idea of all that you plan with this build.. we might be able to offer more help.
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Old 01-06-2007, 08:55 PM   #9
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Camoguy,,,,my plans,,,,I have no plans, I am "hoping" it will work in some reliable fashion. The barrel is 10" with the gb located 4" from the muzzle.

I have seen a pic of a machined bc here somewhere, it may have been yours as I run across alot of your posts doing conversion searches. Azhonkey's also.

As for the lack of gas to operate, if I have to go blowback I will.
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Old 01-08-2007, 01:19 PM   #10
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Welcome to the x25 team Xhardrock! I learned more about the operation of the ak from this build than any other. Mine, still is a work in progress since I put it down to finish some other projects. Hope to have it done by spring. The snow here lately has been crazy.
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Old 01-08-2007, 08:51 PM   #11
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here is a pic of the ext lips on the magwell(just under the rails toward the trunion) and the bullet guide that was made out of weld and reshaped...thought it might help ya


also the angle of my mag adapter....i would put alittle more angle in it...the straightest shot in that barrel is the best!


Camo wait and see my new conversion! will post pics when i get the parts back from my gunsmith bud!
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Old 01-08-2007, 09:38 PM   #12
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Getit.. a new conversion? uh-oh
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Old 01-08-2007, 10:18 PM   #13
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azhonkey...looks great! i like how u did the magwell at the catch...looks like it belongs there more than mine..

well not very difficult to do but i believe it will be one of the first

to let ya in on it....i bought the barrel from Marty at http://teppojutsu.com/welcome.htm awesome guy to deal with! also look at his design of the 7.62x25 long it is a one off barrel that was built for a well know person in the gun industry that canceled the project(lucky for me)


it will use ak74 mags if possible otherwise make a mag adapter to use currently produced mags(hope not) and resemble an ak74.....havent decided on what furnture yet but that is minor stuff LOL...i will let u in on it when i get the parts back from my friend Randy kline...the sledgehammer...he also does some nice work!!!! he doesnt know it yet but i got a suomi barrel for him to turn down and thread to 1/2 28 so i can use my suppressor on this doubletap clone i am also working on....Thx Randy for all youve done!!

Last edited by getit; 01-08-2007 at 10:28 PM.
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Old 01-09-2007, 07:48 PM   #14
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Thanks getit.
Looks like I need to angle it a bit more as noted previously.
I'm currently waiting on a receiver so at this point I'm test fitting on a botched one.
I don't get alot of free time and the bench is loaded with projects so this will go slow.
Thanks again gents.
HR
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Old 01-10-2007, 08:07 PM   #15
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Default Lightning the Carrier and Piston



I took this carrier and piston down to 8 ounces to get my 9mm gas operated to cock and eject. I am running a 16" barrel with a .203 port located 6.5" from the base of the cartridge.
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Old 01-12-2007, 10:36 PM   #16
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azhonkey- I do like how you have done the mag release. Your sights are cool as well... I have yet to decide what to do about the rear sight. I have that long barrel and I don't want to short of a sight picture. I am toying with the idea of a flip down sight mounted on the original rear sight base but put the site leaf/slot mid of the top cover..maybe. Also maybe put fixed sights in the original spot and add a side rail and with a rail mounted on a scope base and put a rear sight on that...would be adjustable and scope ready.

Getit- that is a big barrel...I like it! What the heck is a 7.62x25 long? I was making an adapter to use 30 carbine mags for heavy bullet 7.62x25 bullets... is a 30 carbine mag smaller than a 74 one? I don't own any 74 mags.. but if they are the same size or close I may try one of those....good idea getit!

Holy Cow Rodger! You really lightend up that carrier.... I like your idea on the tube ext to act as a piston rod and just screw the piston in the end. That idea never entered my mind..good call. That would have made my return spring work..better. I have lightend up my carrier some but can take more off if need be. I am making a lighter trigger spring first and see how reliable it is I want some mass on the carrier to make sure the lock up is consistant with that extra inertia coming off the return spring. I am using a FAL adj gas block to play with the gas cycling with the differing bullet weights and power loads. I think the smaller tube gives more velocity to get the piston/carrier moving and hopfully use more inertia to keep it going to the rear with the shorter duration of the charge. If we could get a longer duration
without a super long gas tube it would probably work much better for all of us 7.62x25 tinkerers. What kind of mags are you using Rodger?
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Old 01-13-2007, 12:27 AM   #17
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Default 9mm gas operated

Camoguy
I am running Suomi drums. On the test firing yesterday the spring pressure is still to much on the drum and applies to much drag to the under side of the bolt. The bolt and carrier underside has been built up to allow it to smoothly pass over the loaded rounds in the drum. This is tricky because when the bolt moves back and rotates to lock they have to pass each other and mesh. The gun functions fine with single loads. It fires ejects and cocks but with a drum in place with only three rounds there is enough friction to keep it from cycling.

My next attempt will be to take some more weight off the carrier and clean up the underside of the bolt and carrier more. If that fails I'll start playing with heavier loads and slower burning powder to try to get the pressure up as the bullet passes the gas port. The biggest contributor to cocking load for me was the hammer spring. My solution was to unwind one leg of the hammer spring and hook it over the center support then cut off the excess.

Good luck and keep in touch.
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Old 01-13-2007, 01:04 AM   #18
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camo guy.....the .30 is bigger than 74 round, i was going to use the 74 mag for my new conv, instead i am using 223 mags..fit is much better..the 7.62x25 long is a round that marty designed, along w/ the .338 spectre, .458 socom, and .500 phantom..
The barrel u see is going in the new converted project....guess i will call it the AK6.8 (hint hint) it will be very straight forward.....thinking about having a 223 barrel threaded at the trunion end so i can just swap out barrels and bolt to have both calibers...just need a way to lock it in place

Rodger, hard task at hand w/ what u are trying to accomplish....maybe play w/ the starting surface angle that is first contact w/ round in mag when bolt travels rearward....just a thought....does it pass over the round in a stick mag?? maybe tighter tolerance gas piston to build more pressure?? of course w/o causing more drag
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Old 01-27-2007, 08:09 AM   #19
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Alot of proto work going on by you guys.

Finally got my receiver and to this point I have the barrel sleeved and the mag installed (temp), the alignment looks good for feeding.
Thinking ahead to the gas I believe I am going to "swiss cheese" the bc with 1/4" holes, remove the front end cutting just in front of the ch and attempt to get a FAL piston sleeved and threaded, and for the tube a threaded sleeve for the gb.
That will put my gas hole about 3.5" from the barrel shoulder/bolt face.

Now I need to know why it won't work.
Real busy at work but I'll be checkin in.
HR
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