I just cleaned my BM shorty and used brake parts cleaner to clean the chamber and the upper. When I did this a coat of grease came off of the inside of the upper. Has anyone else had this happen. I touched the inside of the upper and the grease must have been baked on casue it only came off with the brake parts cleaner. I am just going to use clp to lub the bolt and bolt carrier, or should i re-grease the upper.

It's not grease.

Bushmaster applies a baked dry lube film, similar to what's found on USGI magazines inside the upper receiver where the bolt rides.

I would be very careful about what solvents I use to clean this area, unless you want to remove it.

Should I re-dry lube it, and if so how. Or should I just use a good lub.

I wouldn't.

You could reapply such a coating but no way to bake it on the upper receiver unless you take the barrel off, otherwise you fry your lock-tite, etc......

It comes off anyway during bolt carrier break in. So at this point, kinda like refinishing magazines I don't think it matters except from a purely cosmetic sense. This dry lube is more important for a new rifle prior to break in, or one that can't be adequately lubed in the first place(like in Iraq).

I doubt you will notice any difference in operation in a properly broken in weapon, since much of the coating is probably still there anyway. However, in the future I would be very careful what solvents, cleaners etc..... I use on the receiver(I only use solvents on the barrel and bolt).

When in doubt use oil or breakfree only and wipe lightly. They will clean the gun adequately. And lightly coat the upper receiver with a light coat of oil, and clean the gun after shooting which helps prevent carbon from sticking and setting up in the first place.

That's one of the biggest problems with trying to get the AR white glove clean. To do so requires one to remove much of the protective finishes.

The military has been doing this for years with little ill effect.

BTW, as for lubing this area I use a small paint or acid brush to lightly brush gun oil, etc.... into the upper receiver. I don't use grease.