I recently obtained an older A1 large hole AR-15 upper.  I was told that this upper and parts was made by Colt.  There are no markings on the upper receiver or barrel.  I looked on ]www.biggerhammer.net[url/] and saw an unmarked A1 upper pictured there that says it is a Colt upper.  Was there a time before which Colt did not mark their upper receivers and barrels?  Just trying to find out if this is a possible explanation for what I have.

I bought an unmarked, large hole A1 upper that the owner swears was on his SP1.  So it could be true.

When Colt first brought out the AR, and they were the only maker, there was no need to mark the pieces. Then when the govt. gave M16 contracts to H&R and GM's Inland Div., and aftermarket makers began to make copies for the civie market, Colt began to mark their stuff the "C" mark.

In the past few months I've acquired an early M16 upper with no markings except the tiny Colt proof marks just above and ahead of the ejection port, and an early chrome bolt/carrier assy w/o notches. The bolt has the same "M" on it that's shown on the Bigger Hammer pic of the early chrome. Otherwise, both pieces are unmarked.

Barrels I can't swear to, but I would think that the early ones would have had at least an "MP" mark on them somewhere, though possibly not in front of the sight tower, where they later ended up[:D]

I have a 4 digit SP1 from 1967 that has no markings on the upper receiver or barrel(which is pre-chrome bore), so it is very possible that you have an unmarked Colt upper.

Thanks guys for the info.  I also called Colt and was told that bolt carriers, barrels and uppers prior to 1973 are not necessarily marked.