Built my first AR.  Love every bit of it, but after a good 2000 rounds I started running into feeding issues.  Thought it was the cheap hexmags I was using so I bought some Magpul mags and thought I was having better luck until my last trip to the range.  About 20% of the time, the bolt will catch on the round being fed, almost dead center on top in, with the round about to be chambered.  Also, about 5% of the time, the bolt fails to catch open on an empty magazine.  The mag is definitely seated (I shoved a hexmag in too hard once) so I know that's not the problem.  Is the problem with my bolt?

Spikes upper/lower and buffer.
Reign Supreme BCG and bolt.
16" Green Mountain barrel.

Any advice would be appreciated!

Its short stroking, so check your gas system. Gas rings on bolt, gas carrier keys being loose, gas block loose, ect.
Try another BCG if you have one. If it still does it check your gas block for leakage.


 

Thanks a lot I'll check that out!  Would you recommend an adjustable gas block?  Never saw the need for it, but I didn't think it was a gas problem either.

You have 2000 rounds down it problem free it sounds, so it is something that is just starting to happen. You can do an adjustable gas block, but that won't fix it if you have a bolt problem.
Just check it out and find the problem. I have a bolt with less that 300 rounds down it and noticed I have one gas ring missing 1/4 of it, so things happen. Mine is still cycling but, I have other issues with this gun.


 
Is this with the same ammo that you have been shooting? If you just started shooting tula or some other cheap shit it might be the ammo is under powered.

Gas rings are all there. Gas tube lined up. Gas block is tight. Could the gas tube be clogged?

No.

ETA:  What kind of ammo?  Do you keep the rifle lubed?

Adjustable gas block can only restrict the flow of gas, not increase it.

I am having the same problem. I recently added a new low profile gas block to my AR and now am switching to higher quality one... still working on my problem though!!

Very frequently this is a result of misalignment of the gas block.

Check u gas key .  Sometimes the screws snap off and you can't tell since the head is staked. Just try to gently tighten the screws.  If one is broken the head will spin.