Hi all. So I've been told that the MP15-22 has a milspec buffer tube, ie buy a milspec replacement buttstock.

For the regular 5.56 MP-15's, it is commercial.

The stocks from my 2 above rifles are interchangeable and I dont see any difference in how well the stock fits on the buffer tube.

Can someone clarify if indeed the 15-22's are milspec and the regular caliber MP-15's are commercial, and if there really is a difference in the buttstocks? (Eg a milspec vs commercial magpul ACS...)

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ΜΟΛΩΝ ΛΑΒΕ

The 15-22 is 1.150.. milspec... but I've heard people. Say the other will fit but just alittle more play in it

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07/SOT2
NRA Instructor

Been wondering that myself.

The diameters differ as the nice drawings above show.

A stock with a larger civspec hole it it will fit on the smaller milspec lower receiver extension, but not vv. There's a 0.020" difference. But there really is no civspec and it can be anything.

The M&P 15-22 lower receiver extension is milspec.



-- Chuck

Try an aftermarket stock. The OE stock on the 15-22 just might be for a commercial tube. That would explain all of the slop in the fit. I picked up a Magpul MOE for a mil-spec tube and it fits like a glove. No play at all.

Be careful though, I have a .223/5.56 AR, that appears to have a mil-spec buffer tube, but, is in fact a commercial tube. Even when I took it in to a OLL shop, the guy behind the counter said "oh, thats a mil-spec" and to make sure, he tried to fit a mil-spec buttstock onto the tube, but, it would not fit as it was too small...so, I have a commercial buffer tube.

The .22lr M&P I am told has a mil-spec, and, the M&P buttstock will not fit onto my other AR, so it must be mil-spec for sure, as my other AR has a commecial tube.

How weird! My tube on my MP15-T has 6 holes but no slant back. AND seems to be only 1 and 1/8 inches in diameter. Smaller than either of the measurements on the chart. Plus is interchangeable with my MP15-22 stock.

*** did S&W put on this rifle? (The MP15-T)??

I've never seen a "slant back" lower receiver extension. But, then again, I don't look at every one I pass at the range.

Number of adjustment holes is no determination. My original military telestock had two positions: Open. Closed.

-- Chuck

Here... now you can say that you have The slant isn't very pronounced. Perhaps you just hadn't noticed.

Bushmaster 'slant' commercial lower receiver extension... aka Stock Tube.

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Dumb question...what is the point of a commercial tube? Is there an advantage of it over Mil-spec? It would seem allot easier if there was just one kind, instead of making people guess what the heck they have on their rifles, if they did not build them.

I totally agree with ledman. Btw, I was just told that ALL M&P rifles, including the 223/5.56 versions, are milspec diameter. Guess that explains the wiggle in my CTR stock.

Does the 15-22 have a MilSpec or commercial size receiver extension or buffer tube?

LMAO. did you really just ask this exact same question literally minutes after i posted the answer in the thread immediately below?

Confused about buffer tube (commercial or milspec)

must be the night for stock-shopping.

good luck! (and welcome to the forums!)

like everything else... one is stronger... the other is cheaper (ie weaker).

To answer your question, the receiver extension tube is mil-spec. A commercial stock will fit over the tube, but will have excessive play. If you are looking at stocks, stick with the mil-spec and you'll be good.

I attached a milspec moe stock to my 15-22. Fits like a glove.

Hi I'm new to the forum and hoped you could help clear up some confusion. I have a m&p 15 sport and bought a Magpul ACS mil spec stock to replace the factory one. The issue is that in order for the new stock to be installed I would need to force it which raises a red flag.Sorry for being long winded but does anyone know if the "sport" version is mil spec?

Pretty certain they are all milspec buffer tubes. I bought the standard milspec MOE stock and it fits pretty perfectly. It is more snug than the original stock, so maybe that's the issue you're having?

You posted this in the M&P 15-22 forum (for the .22 version of the M&P rifle series). The 15-22 has a mil-spec faux receiver extension. Any mil-spec stock should fit on the 15-22.
I don't' know what the M&P 15 Sport has, but it sounds like it might be a civilian receiver extension. On my BCM lower my MOE mil-spec stock fits snugly, but it's not tight and I don't have to force it.

my 15-22 has a mil spec. tube i just put a magpul stock on it and it is a perfect fit. the org. s&w stock that came on it was looseee.

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N2GUNS

My Sport and my 15-22 are both Mil Spec. Just picked up a CTR for the Sport and had no issues with the Mil Spec sizing.

I'm assuming you are following the instructions:

http://cdn.magpul.com/downloads/ACS_MANUAL.pdf

FWIW I have a Battlelink minimalist stock, commercial, on both an M&P 15 and a new 15-22 sport. I can't tell the difference.

Threads been dead for 5 years, mate....