I bought a optic ready version of a M&P 15 and after about 150 rounds, one side of the gas key in the front is shiny and the opposite rear side shows the same kind of wear. Is it possible the gas key was improperly installed by S&W or something is amiss inside the upper? Seems like the gas key is mounted at an angle.

Attached Images

	DAB2A64A-E934-40F7-AD4D-A1929F04AC15.jpg (46.9 KB, 168 views)
	5E26C7A8-F8E0-4E1A-8620-0E8B4D5C2808.jpg (39.8 KB, 169 views)
	040573B3-0722-474D-A93A-42F9C8C7EFC2.jpg (54.9 KB, 163 views)

Very possible. Best thing to do is contact S&W and get it checked out under warranty.

__________________
Peace was my Profession

Figured. Just thought I would hit up the knowledge here first before I went through that process. At least this deals with the upper and won’t have to worry about the FFL part of it all.

Very doubtful... the key sits in a machined cut out... no where to go.

Part of the violent operation of a fire arm.

I agree. It looks like the gas key may be not installed correctly (canted). I would contact S&W for warranty repair/replacement.

Yep everything from Smith & Wesson is canted.

Ha ha! Your comment peaked my curiosity. So I just checked my ARs.

My M&P10 gas key has the same wear pattern as the OP. My home built AR15 has wear but it is even. It might not be a warranty issue after all and be in tolerances.


Sent from my iPhone using Tapatalk

I’ll have to check my older sons bcg. They both have the sport II’s. Thought about installing Nitride bcg’s in their rifles and keeping these for spares. I know it wouldn’t hurt their feelings. My Sig 516 shows no wear like this.

The one I looked at today has the same pattern... every other AR I've been inside (several) all have some sort of wear pattern all it's own.

Never gave it another thought other than to put a little lube in the wear area.

The zoomed pic makes it appear very exaggerated imo. Normal wear. Lube it

I use grease on the BCG except for the rings and bearing surface of the bolt. I run them very wet. Grease/oil is cheap.

The big question is....Does it work? If so it is a non issue!

It works great.

Looks fine, keep shooting

__________________
^Cat looks like a burrito

Here's mine after 3,066 rounds:



Feel better?

__________________
Freedom isn't free.

I think the rotation of the bolt causes the carrier to attempt to rotate and that is normal and I would shoot it and not worry unless the wear increases dramatically. Normal break in wear on the finish should be expected. I run my guns wetter than recommended until they are well broken in to help keep any galling to a minimum. Not overheating them helps prevent damage as well,despite what the media thinks AR’s are not machine guns.

__________________
Hue 68 noli me tangere