bolt catch broke today on the pof 308 i just put together, the bottom broke off below the pivot hole. i havnt had this happen on a ar15 yet and this is my first ar10 type weapon. is it normal for these to break on one? is there a special catch i should use? only a box and a half of rounds through it so far. after the first 15 rounds it seemed like the spring got weak, but no other problems.