I realize that detailed pics would be ideal, but that would take a while and be a headache, so I'm hoping this suffices, so here's the deal:
I recently picked up a used but nearly NIB Sport II, from a guy I've dealt with before on the local classified sites. But, he said he got it from another guy.
Anyway, I noticed that the bolt carrier has a very grainy parkerized-type finish, that looks kind of dark-green under good light (almost like the old green parkerizing in WWII-era guns).
It appears to be very thick and high quality, but just........unusual. I've owned a couple other Sports before, and this finish seemed unique: more abrasive and greener.
I just went by the big local gunstore to take a look at their Sport II's, and the 2 carriers I saw there had a much smoother,blacker finish that this one has, more like a nitride treatment than a parkerizing.
The inside of the carrier is chromed, and the bolt has an MP stamp on it.
I wouldn't think anyone would be stealing a BCG from a budget rifle like the Sport II, and replacing it with something even cheaper (especially not with one that has a MP-stamped bolt), but this seems a little peculiar.
On the way home with the new toy, I briefly pulled into a spot in the woods I know of, and ripped through a quick magazine, just to test her out, and she ran flawlessly.
So, am I whining about nothing, or is there something amiss here?
Any factual input (or reasonable speculation) would be much appreciated.......

C'mon guys, seriously? Nearly a hundred views (so far), in the M&P15 sub-forum, on THE Smith & Wesson forum.......and nobody's got nuthin' ?
Fo' realz,yo?

Without any pictures and it being a used gun... how would we know?

I don't own a Sport, but parkerizing is a rougher finish that holds more oil for both lubrication and protection from the elements. Blued WWI rifles were parked at arsenal rebuilds when re-bluing would have been just as easy.

After holding and shooting many Garands and Carbines from WWII, I guarantee it works. Imagine the condition in which some of those rifles were used. Their condition today is almost miraculous. The extreme roughness wears off with a few magazines, but enough remains to hold a substantial amount of lube.

With a MP stamped bolt, somebody somewhere along the line put in a superior BCG without going to the expense of buying one of the nickel-teflon, nickel boron, titanium nitride coated, etc. bolt carriers.

Lube it and shoot it.

Sport bolts were MP stamped. Unless they have changed, the BCG is the same in the Sport as it is in the rest of the lineup. This was true with the original Sport with the 1:8 twist barrel, so it is possible that it no longer applies to the Sport II... but someone on here that owns a Sport II should be able to verify the markings on the bolt.

Obviously, I was hoping some of the Sport II owners (which I would think would be in abundance here) would be able to tell me if what I described sounds typical, or odd.
As I said, this BCG appears visibly different from what I remember my others being, and definitely different from the 2 I saw in my LGS yesterday. I figured there would be knowledgeable folks here that would be able to provide some info on way or the other, merely based on my description.
It really wasn't that complicated.

Thanks ! I was particularly wondering about the MP-stamped bolt. Non of the stats or reviews I went through provided that info.

I believe there was a time that Sport II bolts were MP marked but these days they are not to my knowledge. The marking went away around the same time as the 18 twist IIRC. Higher end S&W rifles list the MP an HPT testing IIRC but the Sport II does not. Many people speculate that they are the same bolts but they skip the testing on the Sport II to save $$$.

It is more complicated than you would think. Sport IIs are not all the same. They have changed since their original introduction. You have also given no information about which version of the Sport II you own.

Does it have the forward assist and dust cover? Did it come with a Magpul rear sight? Is the mysterious green bolt a FA BCG or is it SA? This info would help people narrow it down.

To be honest pics of the bolt would be best if you are unwilling to give more accurate info its hard to complain about the responses you are getting.

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Use should dictate gear!

WVSig, I think you are confusing the Sport and the Sport II... Sport II has always had the 1:9 twist, with dust cover and forward assist.

The original Sport had the 1:8 twist, 5R rifled barrel, without FA or ejection port cover. It also had the LMT chopped carry handle rear sight.

Sport, generation 2 switched to the MBUS rear sight. The market wanted folding sights and they were cheaper! No change to MSRP of rifle though. Cost savings plus met market demand! Win Win! At this time, the bolt was made by Microbest, and was the same bolt used in the rest of the line.

Sport, generation 3 switched to the 1:9 twist barrel. You may be correct that the bolt was changed at this time as well as a cost savings. I have no first hand knowledge of the rifle at this point and going forward.

Then, along came the Sport II. Same rifle as the 1:9 twist Sport, with the addition of the FA and ejection port cover.

But I do agree... we need more details and pics, otherwise it is just a WAG if the OP's bolt has been swapped.

The way you describe the finish on your BCG is exactly like mine is. I bought it a year ago and as it was my first AR, I never questioned the somewhat crude texture on the BCG.

I think you are right. My minds not right today LOL.

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Use should dictate gear!

Thanks for the replies, guys, and apologies if any of my comments came off as being unappreciative or antagonistic. I think I'm just getting crotchety in my old age !!
Anyway, the bolt carrier is the semi-auto type (i.e. with the extra cut out material).
The carrier finish only appears greenish when under very good light (flashlight), otherwise it basically looks black. But there is a definite green hue that is noticable in contrast to the gas key and the bolt.
And it is definitely a different looking finish than I saw on 2 Sports yesterday at my LGS.
The bolt does have the MP stamp. Am I to understand this is NOT typical of the newer Sport II ? There's been some conflicting info on this.
Anyway, thanks again for taking a swing.....

No problems. In the end if it shoots I would not worry about it.

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Use should dictate gear!

PSA's Premium BCG's are the same finish. And, they even state it on the package as well. Just lube 'er up and shoot the BAJEEBUS out of it!
If you want a BCG in a nice, smooth, black, Parkerized finish, then buy a BCM BCG.

BCM Bolt Carrier Group MPI Auto M16

I own a 1 generation Sport and there is no HPT, MP stamp any where on the bolt.

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NRA member since 1974

You sure? Which gen 1 Sport? 1:8, 5R twist? If so, you would be the first I have ever heard that the bolt was not marked MP.

I own two M&P-15 Sport II's. The first one has a gray-green finish on the bolt carrier as you describe. The other is a darker gray - almost black - finish. Both have "MP" (no &, just the two capital letters) stamped on the underside of the bolt. I take them to both be genuine so some variation in the darkness of component finish seems to be expected with S&W.