The most common problem is these rifles will function fine with steel case ammo but not so well with comercial brass case ammo. First I tried replacing the firing pin springs,liked some brass ammo 20-30% would not fire even when struck twice. Tried handloads with a variety of brass cases full length resized still got misfires,tried neck sizing results not much better then full length sizing. Now I should mention I've 40+ years of experience in reloading. At my wits end I was poking around the various sites of reloading equipment and stumbled upon a set of shell holders of different heights from Redding to move the shoulder back that range from .002-.010 in .002 increments. Figured what the heck and order a set,used them as instructed and low and behold they worked. I loaded 20 rounds and all went bang on the first firing,I know this may not be a good sampling but before this I got 5 maybe 6 rounds to fire 2-3 miss fires and the pattern would repeat. I'll loading up a batch of 50 rounds with some cast bullets and see if my luck holds up.