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Posted: 7/4/2026 10:59:48 PM EDT
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https://imgur.com/a/9R0inSS KAK K-SPEC enhanced buffer with a flat spring, 4.7 oz. The best I could get it to do was 2 rounds, and it was very inconsistent. Other times, it'd have failures to feed and wouldn't even pick up a round sometimes in the second picture you can see the bolt not go back enough to grab another round. It worked perfectly fine without SS and with an H1 buffer and regular spring, so I know it runs. I think it's just under-gassed. Where do I take it from here? Should I try an H1 buffer with a regular spring, or keep the H2 buffer and get a lighter spring? |
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Lets back this up, and is this a full auto rig, or semi running FRT instead. My guess, FRT and the trigger reset to allow you to pull the trigger again is happening too fast, the B/C still too far back that it allowing the repeat pulls of the trigger too soon, and the bolt locked half way back on some of the cycles as the released hammer is catching the B/C mid return to lock it up, or in other cases, the B/C farther forward, but hammer riding the back of the carrier/Firing pin forward instead. To understand this, pull the B/C out of the rig, pull the bolt all the way forward, then push the FP forward, and note that the FP can not protude out of the bolt face. The allows the released hammer to ride back forward with the carrier on the FP and when the bolt goes to lock up, not enough FP Jolt to primer as the bolt cams over and allow the FP to protude, to ignite the primer. So on that note, get a hold of who made the FRT, and get instructions on how to re-time it for the rig or send it back so they can retime the trigger reset. With FRT, the free gap timing can be slightly larger than full auto rig hammer release from full auto sear rig,since you need to pull the trigger again to release the hammer again. And no, its not a bolt bounce problem. If full auto rig, then still applies, https://www.ar15.com/forums/ar-15/M16-dead-trigger-with-round-in-chamber/66-727293/? And just a note, I know of No Gun Smith that is going to touch a FRT to tune it/correct its timing for the rig is being installed. Also, double check the disc gap to hammer tail as well (should be a free gap of .003" when hammer is cocked back to just mill the disco hook with trigger untouched, Since this may the problem even before problems with the FRT, with disco not retaining the hammer until trigger forced back in the first place. |
Posted By PlaymoreMinds:
'Twas not the <cough> sweet and innocent <cough> PlaymoreMinds...
<---skips away in frilly skirts to Candyland, leaving gutters and snorkels FAR behind.
'Twas not the <cough> sweet and innocent <cough> PlaymoreMinds...
<---skips away in frilly skirts to Candyland, leaving gutters and snorkels FAR behind.
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Check the "Rate of Fire Trigger" subforum. It is dedicated to super safety/forced reset/assisted reset devices and there are numerous troubleshooting threads for different designs. An H3 buffer (5.4 oz.) with tungsten weights or a Tromix H3 sliding buffer is pretty much universally recommended. Mine improved with a stiffer hammer spring also, but if you haven't tried a proper H3 buffer that is where I would start. ETA It's possible you are under gassed as well, but at least some of your issues sound pretty typical of bolt bounce, which is what the H3 buffer resolves in most cases. Hotter ammo will cure the undergassing, if you're running .223 spec ammo some 5.56 might help |
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