Upper receiver marking

[eschoendorff]

Hey guys

The other day, I noticed a stamped mark "M4" on the front face of my upper receiver, just above the delta ring. Any idea why that mark is there or what it means?

 

[thecatch8]

Not trying to be a jerk....have you tried google searching m4 upper?

 

[eschoendorff]

Nope. Why search google when the best answers are generally found here?

In any case, I thought that Colt held the trademark for "M4." I was surprised to see it on my M&P. I wonder if I wound up with a Colt upper somehow (from the factory).

 

[thecatch8]

Nope. Why search google when the best answers are generally found here? In any case, I thought that Colt held the trademark for "M4." I was surprised to see it on my M&P. I wonder if I wound up with a Colt upper somehow (from the factory).

You can't be serious?

 

[BillyJack2012]

Pretty sure he is serious and why wouldn't he post the question here? This is the M&P forum where people come for information? I'd rather welcome a member than turn one away.

OP, Do you have a pic of this? I haven't noticed a stamp like that on any of my upper receivers.

 

[WU_Who]

I would assume it is to say it has M4 feed ramps. Kinda like the "F" marking on some front sight post saying it is for "flat top" receivers.

 

[thecatch8]

I would assume it is to say it has M4 feed ramps. Kinda like the "F" marking on some front sight post saying it is for "flat top" receivers.

OP never mentioned type of rifle, and if he is running a S&W, he does not have M4 feed ramps. M4 feed ramps I think was a Colt design, that has the ramps actually cut into part of the barrel to help with feeding, and to preclude jams. I could be wrong, but that is my understanding.

 

[cyphertext]

OP never mentioned type of rifle, and if he is running a S&W, he does not have M4 feed ramps. M4 feed ramps I think was a Colt design, that has the ramps actually cut into part of the barrel to help with feeding, and to preclude jams. I could be wrong, but that is my understanding.

M&P rifles have M4 feed ramps... Crack your S&W rifle open and you will see them cut into the receiver.

May have been a Colt design, but most AR's produced today will have them.

 

[thecatch8]

M&P rifles have M4 feed ramps... Crack your S&W rifle open and you will see them cut into the receiver.

May have been a Colt design, but most AR's produced today will have them.

Good to know....S&W doesn't mention this on their site, and I don't see it stamped anywhere on my 15T.....where is it supposed to be stamped?

 

[cyphertext]

Good to know....S&W doesn't mention this on their site, and I don't see it stamped anywhere on my 15T.....where is it supposed to be stamped?

It isn't stamped anywhere that I am aware of... that is the OPs question... what does that stamp mean?

I don't recall seeing it on my rifle either, but would help if we could see a picture.

 

[WU_Who]

The stamp is on the front face of the upper receiver behind the delta ring. Saw it when I installed a low profile gas block and different handguard awhile back.

 

[Rastoff]

I'll bet this is what he's talking about:

I'll also bet it indicates the M4 feed ramps.

I always thought the feed ramps were part of the barrel/chamber not part of the receiver. Learn something new every day. I don't know why I didn't notice that before.

Neither of my two keyhole uppers have that stamp. I don't know about the last one because the forearm is blocking that spot and I'm not taking the forearm off just to see.

 

[eschoendorff]

I'll bet this is what he's talking about:

I'll also bet it indicates the M4 feed ramps.

I always thought the feed ramps were part of the barrel/chamber not part of the receiver. Learn something new every day. I don't know why I didn't notice that before.

Neither of my two keyhole uppers have that stamp. I don't know about the last one because the forearm is blocking that spot and I'm not taking the forearm off just to see.

Yup, that's it. I was just surprised to see "M4" on an M&P 15 because (as I understand it) "M4" is a Colt trademark. I was wondering what the marking meant, that's all.