Had the failure to eject problem with my own Bushmaster shorty. Tried doing the basic cleaning, no dice. Tried trading out the bolt, and it still didn't work. Threw up hands in disgust, damning all ARs, and their designer.
I finally went through it with a fine tooth comb, and the help of USMC Col. Bob Young (ret), and the ULTRA detail cleaning did the trick. This gun is just WAY more dirt sensitive than my other AR15s, so I keep close tabs on it now. I clean it EVERY time I shoot it. I clean it if it hasn't been shot. I clean it WHILE I am shooting it.
The problem has not remanifested since the hypercleaning strategy was put into effect.
I still don't trust it though...
It may well be the ideal weapon for Martha Stewart, but not for me, thanks.