I was at the range earlier and was using one of my rarely used AR pistols. It is an aero precision lower. As I was shooting, it works for the most part but occasionally I would go to pull the trigger and here that dreaded “click” sound. I have to cycle the charging handle and eject the round, cycling the next round in the magazine. It will continue to work for another spontaneous amount of rounds before it does it again. In a 30 round mag, it will do it anywhere from 2-5 times. Upon inspection of the ejected rounds, I find they are whole. However, there is a small indent in the primer showing that the firing pin struck the primer but was not able to puncture far enough to get it to ignite.
I used the mags and the ammo in other ARs and it all works flawlessly. So I am confident it is the rifle. It is rarely used so I find it hard to believe anything is necessarily broken or damaged. I inspected it and its not even dirty.
My question is does anyone know what the most likely culprit is? I was wondering about the firing pin but another buddy was saying it could be the buffer spring. Any suggestions?
I really appreciate your help.