fired about 100 rnds from brand new,  very pricey barrel today with no problems.  XM192, SA, WWB.  Then i popped in a mag of portugese that i have fired withno trouble with my stock bushy M4gery.  
gun fired, tore rim off case and jammed another under it
cleared gun
tried again; same thing
cleard gun
fired all three typesabou 15 rnds)  through both mags with about no problems
tried the Port. one more time, examined round and tried new mag, same thing
jammed real hard.  
Now my cam pin will not clear the key when i try and remove it ( i din't kow that it did before i left fore the range)...i know
other than the stupidity of doing it 4 times in 15 min,  anyone got any ideas.  

Brand new CMT upper, CMT BCG & CH

Did you turn 180 and try again.

Tagged for outcome.

i tried turnig it 180,360,540,720....with no effect
My key seems to be staked very well.  To bad they had to get that part right on this one.  I will contact vendor and let you guys know what comes of it.  

Buy yourself a complete Bushmaster carrier & bolt . Problem solved.


Throw away that crap & don't look back.

With all those problems you were discussing, you may have gotten a good bit of carbon build up around the cam pin.  Mine gets a bit of a ring around it.  Have you tried to put a little english behind it and give it a yank?  It may just be held in by a carbon deposit.

Quoted: Buy yourself a complete Bushmaster carrier & bolt . Problem solved. Throw away that crap & don't look back.

+1
exactly...they are proven reliable to me and thats what i'm gonna do.  I ordered the CTM BCG with an upper build i had done and since i needed a bolt and the vendor didn't carry bushmaster I decided to give the CMT a try.  I wanted to support the vendor and buy the BCG from him because he was great to me and his products are great.  I have not talked to him and i'm sure he will more than help me.  I just don't like to bother people on the weekend.  My one Bushmaster is TOP quality.  It has never malfuntioned at all. 5000+ And i was not always as good to it as i should have been.  No more!  That once looked over rifle is commin back out.  I guess if it ain't broke don't fix it, but i still got to put a MGI RRB, Match trigger, etc.,etc.,

called vendor this morning,

new bolt++ was sent before i got to the post office with the old bolt.  He also offered to check and polish the chamber.  I declined until i could look at it better and shoot it with the new bolt and a few other bolts.  It shot great with everything else i put through it.  I'm gonna torture test it when i get the bolt.  Well i can't really afford to torture it but i'll shoot till i'm out.  I'll send it back if everything isn't well.  I don't plan to shoot that ammo anymore.  I'll keep you posted.
kb

UPDATE


     Shooting sub MOA with XM193.  100% 450 rounds since problem.  Even shot the Bad ammo.  The CMT bolt was poorly machined.
I got a better BCG and a nice GTS hat for my troubles.  Very pleased with GTS...Dennysguns!  This mid-length is the best weapon I have ever shot and is capable of producing far more than my current ability.  I didn't want to mention who the vendor was until it was resolved but +100000000  for GTS.  Thanks for your help.

I apologize in advance for the hijack:

Quoted: Shooting sub MOA with XM193.

I always hear these stories but I have never seen it.  How do you get military surplus, mass produced 55gr FMJ's, ball powder, etc.... to shoot sub MOA?

Best I can average in my match barrels is 1.5 MOA.  Do some people just get lucky with a barrel that really likes the stuff or something?  I just never found round to round consistency with it.... and it is loaded so hot.

Is that sub-MOA, 5 shot groups, and all groups averaged under an inch @ 100yds?  Or was that just a few groups that were under an inch.... and the rest were bigger?