Having similar problems to another reported here. Brand new 16" XM15. Not reliabley ejecting spent casings, slide won't lock back every time, and many double jams where new round is brought up when the fired case is not ejected.
Have use five different magazines, all have problems. However, when the action is cycled manually with an empty magazine, the bolt will lock back. Have used four different ammo mfg. Winchester Q3131, PMC, S&B, and Wolf, and all have same problem.
Had a guy at the range today try his "Match Grade" hand loaded ammo with all my mags, and problem magically goes away. We pulled the action spring out of the stock and found that it was 13" long. This guy says he uses 11 1/2" springs in this type rifle. Could this be a source of part of the problem? Makes since that if there is too much spring the bolt may not be able to cycle all the way back with standard mfg. ammo. Do you all think I am on the right track here, or should I just send the gun in to Bushmaster?
As to the ejector problem, I'm still thinking on that. Put a little after market rubber thing on the ejector spring which is supposed to help, and will try that tomorrow.
Thanks in advance if anyone has any commennts or suggestions.