Nick Yes it could be undergassed.....always function check a new piece....one round in mag....charge it.....fire....look to see if the bolt catch holds back the bcg....that's where you start. It has to hold back with bolt catch ! Not ejecting with force is undergassed....needs to be a bit more forceful on ejecting with a new rifle....and lube up your rifle....they like to be run wet when brand new....... also get you some numbered drill bits to see what size your gas port is , in the range of 43 44 45 46 if it comes to that........you could have buffer/buffer tube /spring problems ...but tackle the hold back bolt catch problem first .... Wash