I have an upper that is supposed to be a Bushmaster 16".  It has an A1 receiver with an "A" that sort of looks like the Alcoa sign on the right side underneath the horizontal adjustment and the barrel is marked "B MP 5.56 NATO 1/9 HBAR".  The muzzle break is pinned Mini Y comp.

This afternoon, I was in a gun shop and they had one identical to mine with the exception that it was a 20" and the guy was saying that it was a DPMS.  All of the markings were the same.  It, however, was on a Bushmaster lower receiver.

What is the deal?  Any ideas? Any other markings that I missed that could be helpful?

It doesn't really matter but I just want to know for sure so that if I sell it as a Bushmaster somewhere down the road, that I don't have to worry about some guy named Bruno beating the crap out of me for telling him something that isn't correct?

The forging marks on the upper may well be the same,. because only three or so companies make forgins, and the manufacturers work off of the same forgings.

Quoted: Bushmaster buys its upper and lower receiver raw forgings from various sources,  just like several other AR manufacturers. The markings on a receiver (upper or lower) indicate only which foundry forged them. the list:  (from biggerhammer) Stamping Source CAF Colt / Alcoa Forge (See above for photo) CH Colt / Harvey Aluminum (1st Colt Forgings) CM Colt / Martin Marietta (See above for photos) DK Diemaco / Kaiser FK, FS, BK, DK, EK, FK, AF, CW, AA, FS Bushmaster LK FN / Kaiser LM LAR / Martin Marietta (Army Spares Contract) Splintered A Olympic Arms CJ

Bigger Hammer's info is older than I am, and that is old.  No reference to any of the new forgings, the splintered "A" isn't just Olympic, although early Olympics had them, A1 receivers, IIRC.  I could go on and on.

The only other markings that I have found is the one on the front sight base and that looks like a crown and it is to the rear of the pin holding the gas tube in place and it is also on the left side.

So what is the verdict?  Is this upper probably, possible, or doubtfully a Bushmaster?

Quoted: The only other markings that I have found is the one on the front sight base and that looks like a crown and it is to the rear of the pin holding the gas tube in place and it is also on the left side. So what is the verdict?  Is this upper probably, possible, or doubtfully a Bushmaster?

I had a factory Bushmaster rifle with those exact markings, came with the Bushmaster hard case, papers, target, the whole nine yards.  Splintered "A" and "B MP.............." barrel.  I'd guess Bushmaster.

Are you talking about your upper or the gunshow guy?  What stampings did he have on his barrel?

Your barrel is definitely a Bushmaster.  Look inside it as see if it looks a bit grey.  Bushmaster puts an extra protective coating inside the upper.

Since you know the lower is Bushmaster and the barrel is Bushmaster, then I'd say you have a Bushmaster.