7.62x25mm Polish Tantal carbine build
 

Hello my name is Joe, during the last 6 months my dad and I have built 10 ak's from parts kits and flats. We had some extra parts left over so we decided to build a 7.62x25mm ak. my dad happened to find a nodak spud tantal finished reciever at a good price so we got a Bulgarian ak74 bolt and bolt carrier and a pps43 lower receiver. We decided to use a cut-off 30 cal Mauser barrel 16.5 inches long that my dad chambered for 7.62x25 and I am in the process of turning by hand with a file. I have finished the trunnion boss and installed the barrel into the trunnion drilled and installed the barrel pin now i am turning the rear site boss down to install the rear site. i do not have access to a lathe so I put the barrel between the centers of my broken wood lathe and turn the barrel by hand as i file it to size it takes some time but it is worth the extra time. I also decided to make it my own design so I am using the pps43 grip and trigger guard instead of AK parts and i am going to use an mp5 forearm.
here are some pictures more to come.

Welcome to gunco.

Looks like an interesting project. :)

Looking pretty good so far. Good luck with it. I didn't see any mention of whether it was going to be blowback or a gas op build? There is information available here for both types.

This is a blowback build, The only permanent modification is the removal of the nub on the back of the bolt carrier the bolt is not modified in anyway and stays in forward most position as the bolt does not rotate. I did not want to make many permanent modifications so if i needed to I can return it to the original caliber.

Man that's doing it the hard way but that's how a lot of stuff used to be done. How are you securing the bolt in the carrier from moving ??????

I have done a bunch of x25 barrels for various projects.

there a bunch of threads on doing blow backs here in different caliburs.

as long as the barrel is far enough to the rear of the trunnion so the bolt does not turn when in battery it will stay in the forward position, I did it this way so that i did not have to open up the back of the trunnion to get the magazine closer to the chamber and I did not want to modify the bolt.

Welcome to the forum

Yeah that's nice so far, please keep us updated

Thanks, I hope to have the barrel components on by Sunday at least the rear sight and gas block so I can test the feeding again and do a test fire to make sure it is going to work properly. I will update with pictures soon and when it is finished i will post a firing video.

I RELIZE THAT BUT THE BOLT WILL HAVE ABOUT A 1/8" OF TRAVEL EVEN IN THAT POSITION . ITS GOING TO BE HARD TO HEAD SPACE LIKE THAT WITH A STOP FOR THE CARRIER AN THATS THE REASON FOR MY NEXT QUESTION THE NEXT QUESTION .

SO WHAT IS GOING TO STOP THE FORWARD TRAVEL OF THE BOLT OR CARRIER WHEN ITS EMPTY ???

WITH THE BOLT IN THE FORWARD POSTION THE CARRIER WILL NOT GET TO THE TRUNION . UNLESS IM MISSING SOMETHING, THE ONLY STOP WILL BE THE BOLT HITTING THE BREACH FACE.

THE OTHER PROBLEM IS SEE IS ALL THE FORCE OF THE ROUND IS GOING TO BE SLAMING THE BOLT INTO THE SMALL 1/8" FLAT PART OF THE GROOVE IN THE CARRIER ITS NOT GOING TO HOLD UP LONG LIKE THAT EVERY TIME IT FIRES ITS GOING TO TRY TO SHOVE THAT LOSELY FITTED BOLT INTO THE CARRER GROOVE AN THAT GROOVE IS NOT VERY BIG . iD AT LEAST SUGGEST A TWO PIECE SLIT SLEAVE AROUNG THE BOLT STEM TO TAKE THE FORCE SOME HOW OR SOMETHING ELSE .
ALSO THAT HAMMER IS GOING TO TAKE ONE HELL OF A WACK IF THERE IS AN PLAY BETWEEN THE CARRE RAN THE BOLT THAT BOLT IS GOING TO BE MOVING ABOUT 800 FPS UNTILL THE CARRER MOVES . I MAY BE WRONG HERE BUT ID HATE TO SEE EVEN A COUPLE THOUSANDS OF BOLT PLAY ON THE HAMMER WITH NO CARRER WEIGHT . THAT HAMMER IS GOING TO FLY BACK HARD.

AN ADDITIONAL PROBLEM YOUR GOING TO INCOUNTER IS THAT WHEN THE BOLT IS ALL THE WAY FORWARD THE BACK OF IT IS ABOUT A 1/8" INSIDE THE CARRER AN THE HAMMER WONT BE ABLE TO HIT IT. I RELIZE THE SPRING PUSHES THE CARRER FORWARD AN THE ROUND WILL PUSH THE BOLT BACK BUT ONCE YOUE EMPTY THE HAMMER IS GOING TO HIT THE VERY THIN AREA ON THE BOTTOM OF THE CARRIER WERE THE BOLT GOES THROUGH AN PEEN IT OVER OR CRACK IT AS WELL AS BUGGER UP THE HAMMER.

EVEN IF YOU ADDED A STOP TO THE CARRIER OR TRUNION THE BOLT STILL MOVES FOR AN AFT ABOUT A 1/8" JUST DUE TO CLEARANCE SO IF YOU SET IT UP WITH A STOP THAT ALLOWS HEAD SPACE WITH THE BOLT PRESSED BACK ITS GOING TO MOVE FORWARD ON A EMPTY ROUND AN SMACK THE BARREL. PERHAPS IM MISSING SOME THING???? IF IM RIGHT ID SUGEST YOU FILL IN THE FRONT OF THE GROOVE IN THE CARRIER SO THE BOLT CANT MOVE BACK AN FORTH IN ITS FORWARD POSITION AN GET SOME SORT OF SLEAVE AROUND THE BOLT STEM TO TAKE THE FORCE VS THE GROOVE IN THE CARRIER. . BASICALY TAKE THE SLOP OUT OF IT AN THEN ADD A STOP TO THE CARRER ON THE LH SIDE TO HIT THE TRUNION BEFORE THE BOLT HITS THE BARREL . YOU WILL WRECK THE BARREL FAST IF IT HITS. ALSO THESE MODS WOULD ONLY BE DONE ON THE CARRIER AN YOUR ALREADY MODIFING IT BY CUTTING OFF THE TANG.

I AGREE WITH MOVING THE BARREL BACK TO HELP WITH FEEDING .

HAVE YOU ACCOUNTED FOR THE END OF THE BOLT BEING IN A DIFFERANT LOACTION FOR THE HAMMER TO HIT IT. FROM THE LOOKS OF IT THE BOLT WILL BE ABOUT 3/8 TO 1/2 INCH BACK FROM NORMAL .

I HAVE SEEN WERE A 7.62X25 BLOW BACK DID NOT HAVE A STOP AN THE BOLT WAS ALLOWED TO SLAM INTO THE BARREL ITS NOT PRETTY I HAD TO REPAIR ONE FOR A GUY I BUILT THE BARREL FOR THAT DIDNT HAVE A STOP ON THE TRUNION

AN BTW WELCOME TO GUNCO

I have modified the follower in the mag to stop the bolt when empty so the bolt will not hit the barrel and it will have a stop on the trunnion.