I build my .308 semi auto (AR 10 style) rifle. I was having a problem with a round feeding from the magazine because I believe the bolt was cycling too fast. So I either needed a new magazine with a stiffer spring or (what I did) what trim some of the magazine housing back where the rounds are stripped so the round is stripped off sooner. That fixed my problem 100%. However, now I am having a problem where sometimes (not all the time) when I have multiple rounds loaded in the magazine the rifle wont’ fully chamber and lock (pull the trigger and I get a click). Then I need to pull extremely hard on the charging handle to extract the round. However, when I just load 1 round in the magazine it chambers and locks perfect 100% of the time (even using the ammo that previously would not fully chamber and lock when multiple rounds loaded). So this makes me believe that it is not the rifle but still the magazine or perhaps the ammunition. Since I reload my own ammo and bumped the shoulder back about 0.002” could it be that I need to take the shoulder back further, like to SAMMI minimum (usually around 0.005”). Or could it be something with the magazine again since it works with 1 round loaded but won’t with more the 1 loaded (tried with 2, 3,4,5,6 rounds loaded)? It would make since it is the magazine but am not sure. Sorry for the long post but would appreciated some advice? Thanks.