Colt Upper receiver marking question.

[Trepang]

I have two Colt 6721s. One is a 2000 police trade-in and the other I bought new in the box a couple of weeks ago.

This evening I noticed that the newer on has the usual "M4" stamp on the front of the receiver behind the delta ring but the older one is stamped with just "4".

Has anyone seen this before of know the significance of the 4 versus the usual M4 stamp, if any?

[ww2farmer]

Without cracking open some reference material, IIRC that's the way early uppers with M4 feed ramps were marked. They might also be "hand cut" feed ramps as well. Someone with a better memory or more knowledge of the subject will be along shortly to set the record straight.

[Trepang]

Being it is 17 years old, I took it to a gun smith before I shot it the first time. The feed ramps aren't handout. As a matter of fact, he used a RRA to show me the difference between "factory" Colt feed ramps and the "hand cut" ones on the RRA.

It's just more of a curiosity thing. All the other Colt markings on the barrel, upper and lower and the BCG are what and where they should be. The missing "M" just got me wondering if it meant something.

[Ryno12]

Being it is 17 years old, I took it to a gun smith before I shot it the first time.

What's the expiration date? [emoji6]

[JoshNC]

That was common early on with colt m4 feedramp uppers. I have a Colt 6731 upper (same as 6721, sans bayonet lug) bought as one of Colt's complete conversion kits around '96. It is stamped with "4" instead of "M4".

[Trepang]

Thanks. I appreciate the help. That was what I kind of figured - just wanted to make sure mine wasn't some "one off" Colt.

[JC5188]

Thanks. I appreciate the help. That was what I kind of figured - just wanted to make sure mine wasn't some "one off" Colt.

We're never quite that lucky, are we? Lol.


Sent from my iPhone using Tapatalk