Came back from range after testing new handguard and gas block, everything functioned correctly, I did try-out for the first time a box of 180 grain Federal Power-Shok that had recoil for days .. got back and observed this shiny big nick/chip on the upper receiver like a piece of metal was chipped away. All other components look ok..bolt, handle, etc. it looks like it may have been caused by the charging handle violently returning and hitting that edge. Should I be concerned about rust since its exposed metal and what could have caused this?

Hate to send it back to S&W and wait a year on new receiver.

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mine has the same wear i have appx 500 round thru mine no problems

I had a difficult time taking a pic of what I saw when I examined mine, It looks worse than it really is, although yours looks worse.
It really isn't anything to worry about (on mine).

I examined the BCG and charging handle for corresponding wear marks and couldn't see any, but the BCG being steel and the receiver being aluminum, you probably wouldn't.

Aluminum does not rust, and both the upper and lower receivers are aluminum. but even if they were steel, this area stays lubed and would never rust anyway.

Thank you for that knowledge base, did not know the receiver was made from aluminum, explains why the handle marks are all over it. It's just disappointing that on a fairly new rifle this happens and maybe the tolerances or the design is at fault. Either way, appreciate your responses and hope mechanically it does not affect it. I will contact S&W reps and at least they could way-in.

FYI, I do have M&P 15 with over 1000 rounds through it and some marks on the receiver but nothing like this

** the red stuff is gun grease (was so worried about rust greased the hell out of it )

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I suspect that given the higher power of the .308 round, that the receiver flexes a bit and the BCG bites that corner a little at first.
These guns are way over gassed to begin with and I tamed mine down right out of the gates so that might be why mine is minor compared to yours. Once that material is out of the way, it's out of the way.

<disclaimer>
this is all speculation on my part, I am not a smith, I just study the why and how things work as they do, it is a passion of mine and is a major part of my work experiance

Most AR pattern guns I've owned have some wear there. Seems like there is initial wear when new then it stops. The Colt LE901 has a steel insert at that point.

__________________
Cliff
CCSO, FPD ret, USN ret.

Mine has the wear in that exact same place.

101

Mine has similar wear, too.

[IMG][/IMG]

Similar wear spot on my MP15 too.

[IMG][/IMG]

Thank you all for sharing, well I replaced the charging handle with BCM MOD 4 and it actually fits but I noticed this uneven wear ...where did all the metal go? and I assume this is normal too for BCG with less than 1000 rounds

https://www.flickr.com/photos/118379...5/12919041375/
https://www.flickr.com/photos/118379...5/12919455984/
https://www.flickr.com/photos/118379...5/12919462804/

BCM Charging handle - Medium ..
https://www.flickr.com/photos/118379...5/12919153813/
https://www.flickr.com/photos/118379...5/12919474254/
https://www.flickr.com/photos/118379...5/12919168123/

Those little metal flakes probably fell out when you dropped the first magazine.

Did you use the OEM metal magazine by chance? Looks like the BCM made itself some clearance on a metal magazine.

No the one supplied never worked (dry fire) so it was magpul from the get go. BCM charging handle is brand new ..did not fire the rifle with it yet, I was skeptical at first but it works with no clearance issues unlike:
S&W M&P10: BCM Gunfighter Charging Handle Modification - YouTube

Maybe it dragged on the bolt catch somehow.

I've got the same wear also on the outside but not on the inside.

Sigh. So I can't remember all the posts about this, but it is becoming apparent that there are either two versions of this charging handle or two versions of the parts in the M&P 10 that are in contact with it. I wish I knew which I have before ordering one of those...

TXforFreedom:

I did research it, actually I wanted the 'Raptor' since I have one on my M&P 15 and love it, but the risk of it not working and spending close to $100 was too much so I went with the BCM at about half the price and hoped for the best, if it did not work I was going to follow the tube demo. Bravo Company came up with a version two of the handle and its this version that is currently sold ...looks thicker on the end, plus and this is just me guessing the earlier bolt versions of the M&P 10 are little different than later productions, my rifle was made in Sept. 2013... loosened up tolerances maybe ... again just guessing don't quote me.
https://www.rainierarms.com/?page=sh...roduct_id=3335

I couldn't resist quoting you...

My rifle was made probably in Feb-ish last year. I guess I can ask Rainier if I can return it if it doesn't fit out of the box, even though they say:

NOTE: Will NOT fit SIG, Rock River Arms, Bushmaster, Colt, H&K, or Smith & Wesson rifles

S&W should offer a larger latch guaranteed to fit their own rifle. This rifle just begs to have a scope on it and as we all know, it's a little cumbersome to have the stock latch on it with a scope.