Cheap AR Build No Workie
Posted: 26 Nov 2020 20:22
By swapping parts around and hand-cycling I figured the chamber was cut tight on a rig I built. Took a fired case and drilled out the primer pocket big enough to thread for an old cleaning rod I had. Threaded it in and silver soldered it in place, filled the hollow female threads at the other end to withstand the clamping force of the chuck jaws on my cordless drill. Lightly coated the case with valve lapping compound and honed the chamber until I could get trouble-free hand cycling. Had to clean the barrel with every test run.
Then it still misfired but at least cycled when it did fire. Found the firing pin about 0.030" short as compared to another from a fully functioning rifle. Below find the non-scientific comparison. I switched the pin over to retest and ordered a couple stainless replacements. Everything then worked well.
Then it still misfired but at least cycled when it did fire. Found the firing pin about 0.030" short as compared to another from a fully functioning rifle. Below find the non-scientific comparison. I switched the pin over to retest and ordered a couple stainless replacements. Everything then worked well.