***UPDATE NO.3**My new AR is cycling .223 fine but hanging up on 5.56

I just finished a build through PSA and was finally able to do some shooting this weekend. Only put about 100 rounds through it but found that it would not function with 5.56 (American Eagle 55gr). It would not get more than two rounds through it without a misfire. It seemed as if the BCG was getting caught up about .25" from being in full battery. All I got was a "click" and no fire. Ejected magazine, manually ejected unfired round with charging handle and repeated process about 10 times with same results. .223 (Remington express core-lokt) ran fine with no issues. I used the same magazines all afternoon- PMAG's.

Anyone else have this problem? Will this subside after a couple hundred rounds typically? I have no problem just purchasing .223 rounds from now on since that is what the rifle is running fine with, but was just curious as to what the issue could be.

Here is my build parts list-
PSA CMV 16'' 5.56mm 1:7 Carbine Length M4 Profile - Without BCG & Charging Handle
PSA 5.56 Premium Full Auto Bolt Carrier Group
PSA AR-15 Complete Lower Magpul ACS-L Edition - ODG, No Magazine
Magpul PMAG 30 M3 MagLevel, 5.56x45 Magazine MAG556-BLK
BCM gunfighter medium charging handle.









UPDATE NO.2***

Three 5.56 rounds. The one Im holding to the left did not fire but was clearly struck by firing pin. The other two did fire.

I was finally able to get another rifle to help with the troubleshoot. Was getting same results as above - click and no boom. The one thing that was different was that the BCG did go fully into battery every single time today and did not hang up like it was previously. It still ran .223 fine, but would not fire 5.56 consistently (misfire every other round or so).
-First thing we did was fire an entire magazine of my suspect American Eagle 5.56 through rifle no.2 (the rifle that is functioning right) and my ammo ran fine through this gun. We then tried same ammo with same magazine through my rifle (rifle no.1) and it misfires every other round or so.
-We then swapped entire BCG between rifles. Same results. Rifle no.2 ran fine with no malfucntions and my rifle (no.1) misfired on every other round, at one point 5 rounds in a row. The round was struck, but not fired.
-Next we swapped BCG's back to original gun but changed firing pins. Same results.
-Next, replace firing pins back to original and changed buffers only. Same results.
-Next, replaced buffers back to original rifles but swapped buffer springs. Same results.
-Next, swapped both buffers and springs. Same results.
-Finally, restored rifles to all original parts and same results. My rifle would always strike the round but not fire consistently. His rifle, with various combinations of my parts would run fine and did not hang up or misfire one single time. I am truly stumped and am awaiting another call back from PSA at some point this week to help diagnose and hopefully request to send the complete rifle back to them. Dont know if any of this info helps. It seems we eliminated ammo, BCG and firing pin, buffer and spring today. Not sure where this leaves me.



***UPDATE NO.3***
I ended up shipping the entire rifle back to PSA on 2/25/15. I finally got the rifle back last week with a letter signed by their lead technician (Estes) saying that they replaced the entire BCG Assy and apologized profusely for it taking so long. They didnt give me any specifics on what the exact problem was and Im truly stumped because the first thing we did when troublshooting was took my BCG out and put it in a 2nd functioning rifle and it ran fine. The rifle was bought the week before Christmas and is now finally working so that's very disappointing that it took so long but Im happy that's it finally operating. I put approx 200 rds through it over the weekend and it functioned perfect. I'll buy PSA again, and just wanted to follow up for anyone that was wondering or curious.