12-02-2018, 04:33 AM
1075 tech Wrote:Ok. I checked bolt (from first 2018 group buy). Overall length is 2.814. Bolt recess is .134 instead of .136. Within tolerances?
Firing pin length is 3.278 and I have pin protrusion of .0305.
Upon disassembly, I found an excessive amount of oil and carbon. I would like to think this, combined with the below freezing temperatures, slowed it down enough to not ignite the primer.
But that doesn't explain the 2 misfires during the initial function testing in late summer. However, I believe they were early on with a very low round count and these group buy bolts are tight in the carrier.
Any other thoughts?
BTW, all factory ammo. Inthinknthe initial two were with Wolf steel case. The others more recently were with Federal Fusion.
I think your bolt face depth, bolt overall length and firing pin are gtg. Only other thing is if you had excessive head space but I would be surprised if that was the issue. You could measure your spent brass to see if there is excessive growth after being fired this barrel. I suspect you have an issue with the Rise Arm. trigger. Have you got access to a different lower with different type of trigger to test the upper.