I took the new Bushmaster to the range today for the first time.  The ammo used was Black Hills (BH)and Federal M193.   I started out with the BH and the gun jammed continously....I'm talking every shot ...two at most.  I switched mags...same thing.  I switched to the Federal and it worked like a charm...no failures period. The ftf's seemd to be due to incomplete ejection, with the bolt slamming on the spent casing and the "new" round.  I've used BH in other rifles with great success.  Do you think it is a new rifle break-in issue or something else?  

The BH is most likely loaded lighter than XM193, which is pretty hot.  That could be the problem right there.

Which BH were you using?

MT

I threw the box away already....but it was plain old 55gr fmj.    

My Bushy 20" Hbar doesn't like certain brands of .223. I've tried different mags, cleaned and lubed weapon. and still have ftf and fte problems with the same brands of .223.
LC and Q3131A are all I use now--never a problem with the 5.56 stuff. Never tried any BH products. The .223 is now relagated to the mini 14 which seems to like it.