Thanks all for the replies! Now I have some things to look for. Sorry for the misuse of terms, should have said FTI I guess. I will check on all the things that were mentioned. Also, learned a few things, this is my first AR, so I didn't know they liked it that wet to operate, I lubed it the same as any of my other guns.

Yes, the FTI's were light primer strikes, as if the bolt was not foreward quite enough (a few thousanths I am guessing) as far as "knowing" if it was seated properly, I am unsure as to how to check that after I just fired a round. The rounds that I rechambered only went off after I made sure the bolt was seated with the foreward assist, is that not why it is there? .

As far as checking headspace, I will get a hold of some guages and check, guess it is my bad for not checking first, del-ton states that they have headspaced and test fired all their uppers, and I have heard nothing bad about them. Thanks BP tactical, I will also check the pin protrusion. It is a
very infrequent failure. And after I put the failed rounds back into a magazine, the first 4 failed the same as they had before, and the last 2 fired after I bumped the assist to make sure everything was seated properly. As far as metal burrs and such, I will check again. That was one of the first things I looked for when I got home. Also, the bolt carrier is chrome lined, so pretty obvious if something is wrong inside of it. I am sure it is not a gas system issue as it had no feedin problems whatsoever or shortstroking, etc.

Stock- it is a carbine length spring, buffer, and tube. All measured to be proper lengths. ( Had another thread on that!!)

Thanks all so much for the advice! I will check those things and report back as to my findings!