Jump to content
Sign in to follow this  

shells deforming in extractor groove, failure to feed. (tristar s-12 clone)

Recommended Posts

i found an old post from md talking about how to file on the groove a bit, but i smoothed it out a bit and still getting issues... any thoughts?  too thick of a shell rim on the barrel?  wrong angles on the extractor and barrrel groove?   magazine follower angle wrong?  mag catch face too low?

Share this post

Link to post
Share on other sites

Try loading a mag and marking the top of each shell.  Then fire, and recover.  When you know the angle of the deformation from top, then you know where to start looking. 

My first S12 had a narrow trunnion on the extractor side and would deform the lip pretty bad on ejection (shear it off almost).

Share this post

Link to post
Share on other sites

What was your fix? I’m not fully following. Fingers type faster than brain haha 


So did some work on it yesterday... when I was trying to get pictures I had the great idea to turn it over to take picture. It’s deforming on the extractor groove, aaaaaaand the lower 5-7 o’clock groove. So never would have thought of that if evl hadn’t asked for pics. So, thanks!  Now I just need to get itsmoothed enough to be 99-100%. If that’s even possible


Well shoot looking at pics it’s not the grooves it’s the chamber lip. I gotta resize pics n post standby


Edited by saltydecimator

Share this post

Link to post
Share on other sites

In the top pic, it looks like that shell had been ran through more than once and possibly caught on the extractor slot on the first go or a previous go (the bulge on the right at the feedramp, in relation to the pic, not the right of the weapon). If what I think I am seeing is what I am really seeing, they basically skipped a step at the chamber end or decided that it didn't matter enough to copy. Maybe they tested the early ones with very stiff-hulled loads and it simply wasn't an issue that needed to be addressed, from their perspective.

In this pic, the grayish pink is what I think is the area where the rim fits into the chamber. If it is (key word 'if'), you might try taking a little from the slot into the chamber beyond where the rim goes (green area). File, check, repeat as necessary until it no longer hangs there. Worst case, you get a little carried away and the case heads bulge at the slot because you went to far. As long as you do not go crazy, a little bulging should not affect safety or extraction, but may effect the viability and/or safety of reloading the hulls that you fire. I play a gunsmith on youtube, use your head... save your eyes and hands ;)



  • Like 1

Share this post

Link to post
Share on other sites

loooolz, something about kitchen wizards??


i took some off from the green area, by off, i mean i smoothed the top and bottom side a bit, as well as that lower slot ( is that for machining purposes, or what is its function?).  runs better now.... been 25rds of universal without a failure... notta lot i know, but i think i gotta send it in as the bolt carrier has daylight showing through the recoil spring tunnel.  whoooops!



Share this post

Link to post
Share on other sites

I think that would run perfectly if you change your technique slightly. Get more mass behind the weapon. With the shoulders angled and the butt in the 'pocket', there just isn't much mass behind the weapon. I know it may sound nuts, but I put the butt on the collar bone (almost directly below the side of the chin) with the shoulders very close to square to the weapon. Lean your entire torso forward until you feel the butt flat on the collar bone and pull the weapon in tight (looks like you are doing a good job of that part already). There is also less flesh there, which reduces soreness and bruising if you are doing it right. You may have seen it already, but I have a video on youtube with 'Long Gun Shooting Technique' in the title. Have a look if you haven't already or if you could use a refresher. 


That carrier situation is interesting. I would be concerned about cracking in the areas around that milled out area that initiates bolt lockup. It would be interesting to see how long it lasts or if it cracks elsewhere as a result of deficient material in that area. That area isn't very thick in the Russian guns, but I am sure that it adds some level of durability.

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

Tromix - Lead Delivery Systems
Dinzag Arms
Mississippi Auto Arms, Inc
Cobra's Custom
Carolina Shooters Supply
R & R Targets
SGM Tactical
Mach 1 Arsenal
C&S Metall-Werkes
American Specialty Ammo
Csspecs Magazines
Phoenix Technology
Evlutionz LLC

  • Chatbox

    Load More
    You don't have permission to chat.