Failure to fire after trigger rebuild

Hi All

I just rebuilt the trigger with the MCarbo trigger rebuild kit and after two or three rounds, I got a failure to fire. I racked it and checked, the primer was dented, then it ran a couple more shots fine, then it failed again in the same way. Racked it again and got a couple more good shots, then another failure to fire. I didn’t make any changes to the hammer or bolt other than to clean them up while I had the rifle apart. Any suggestions as to what I did wrong?



Have you tried different ammo? If the primer was dented but didn’t fire, could it be the ammo? Or was it a very light primer strike?


Welcome aboard @CaptainHindsight style points for the SN. Possibly the firing pin and channel are fouled. Clean and re-assemble without any oil.


Welcome to the firm @CaptainHindsight .
what ammo and magazines are you using?


Hey All

Thanks for the prompt replies! Here is what I have so far:

  • I was using Winchester white box, tried S&B ammo with the same results. For magazines, I was using the factory mag; using a Glock OEM mag has the same issue.
  • @Festus I field-stripped it, cleaned and re-oiled the bolt and made sure that everything was running smooth. Then I reread your post. I’ll pull it apart again and dry everything out. Is it possible/feasible to take apart the bolt to clean out the channel where the hammer lives?
  • The primers on both the spent and FTF rounds were dented, though it looked like it could have been light.

I did notice something odd: the spent casings on the rounds that went were burned pretty good on one side. I don’t know if that is normal or not but I have never noticed that before.



the same ammo that didn’t fire, have you refired the round in a different gun?


OK, I think I have it figured out. Here is what I did:

  1. Took the rifle completely apart
  2. Cleaned, dried and put a very light coat of oil on everything
  3. Reapplied small amount of PTFE to connection points on sear and hammer
  4. Re-watched both videos and CAREFULLY reassembled the rifle

Took it for a test drive and it ran both brands of ammo just fine. My best guess as to what went wrong is one of the internal parts was just a little off/misaligned, most likely the hammer; it was off just enough to function but was binding up and not striking with enough force. BWT the MCarbo performance trigger kit makes a big difference; it is basically a new rifle.

Thanks all for your help!