A million thanks to the replies (Tumbleweed and TXAGGIECCL). I will bank those suggestions and give them a shot after the next range visit. I want to see what the cleaning did (lots of Gun Scrubber and elbow grease produced a lot of foul black liquid). Also noticed something else, the bolt carrier is notched deeper (i.e. you can see the entire head of the firing pin) on the bottom than the bolt carrier on my Wilson Combat. I am assuming there can be such variations among manufacturers?

Anyway, thanks for the tips.

Not variation, just different generation of bolt carrier.  My Bushmaster from '01 had the notched out firing pin area, and the '05 CMT bolt had it filled in.  I've had no trouble with either and don't think it really matters.  I personally like the notched carriers as they're easier to clean :)  I suspect the newer design might be a fraction stronger since there is more material, but I highly doubt that's why they made the change...as I've never heard of bolt carriers breaking (unless they were a manf defect).

IMHO, It's probably simply just cheaper to machine the carriers without the notch.  Nothing more, nothing less.

The 14.5 inch barrel should be equipped with the black extractor buffer spring.

Installing a D-fender or other o-ring will help, but the black buffer has a higher durometer rating than either the older white or newer blue version.

Per the Colt factory, anything less than 20" rates the black buffer.

The Wolff extra power spring and black buffers eliminated almost all of our FTE's using Bushies at the training center where I work.

Had the same exact malfunction several times last Monday at a law enforcement machinegun demo.  I checked cases that failed to extract and found the rims had strong pull marks.
From that I determined it was a hard pull so I scrubbed the chamber and problem went away till it got dirty again.  Was using SS109 Olympic ammo I never heard of.  Propellent must be very dirty.

OK, let me say up front that I'm no TWEAK, and have only been through one AR-15/M-16 Armourer's school, but shouldn't the gas tube on this shorty be either "fattened" (like i Have on my 10.5) or lengthened, like this pig-tail gas tubes?

To save the information, but to prevent the topic from become to long for easy reference.