If your rifle is ejecting the spent round that was just fired (or not ejecting and can be pulled out) but is failing to pick up the next round, crushing your round halfway up the feed ramps, or stove-piping,  there are a few possible at home fixes.  The first thing to check would be your gas block which would be the two pictures below labeled gas block for reference. To resolve this issue, simply push the gas block back up to the shoulder cut into the barrel, keeping the gas block as straight up as possible, and tighten down the two set screws underneath.  I would recommend some blue loc-tite to help keep the screws from vibrating back out again.

If your gas block seems to be in the right place and your rifle only experiences this malfunction every few rounds then it may be the gas rings have aligned (picture).  Normally the manifestation of this malfunction would be a stovepipe or the round getting crushed on the feed ramps (pictures below).  This is something that should be checked with every rifle maintenance session and is as easy to fix by un-aligning the rings.  


Please let me know if this has been helpful below!