Okay so on the last round of my magazine, my bolt does not lock back. This is weird because whenever I manually pull the charging handle back on an empty magazine, it locks back just fine. Could my gas block not be aligned properly? Also, i am using a standard carbine buffer and my rifle has a mid length gas system. I just recently went from a spikes T2 buffer to the carbine buffer and I notice that my rifle is cycling noticeably faster. Can the rifle be cycling too fast for the bolt to lock up on the last round? I feel like there are many possibilities to why it is doing this but I just want my rifle to work the way it should. Thank you.
It is a rifle that I built. It is a spikes upper with a spikes nickel boron bolt carrier group. Daniel defense government profile mid length barrel. Spikes forged lower. Geissele SSA-E trigger. Spikes buffer tube and magpul CTR stock. (A lot of the spikes stuff was on sale when I was buying all these parts)
Well technically it was broke because my gun was not extracting rounds off the face of the bolt and the gunsmith recommended going down to a lighter buffer but actually I just had spikes send me a new bolt and that solved the problem and I just left the carbine buffer in there because I liked how fast the rifle was cycling
Like Steve said, try a heavier buffer and see if that solves your problem. If it is cycling too fast it could potentially cause the bolt to not lock back. Let’s rule that out before we start looking at potential short stroking.
I midlength should function with an H buffer, especially the DD. I assume that since you assembled this, did you align the gas block correctly? Especially since DD barrels are not dimpled for use with low profile gas blocks.
Yes. If the bolt comes forward too fast, the magazine spring wont have enough time to push up the next round. This would result in the bolt closing on an empty chamber.