Confused about buffer tube (commercial or milspec)

[DavidRSA]

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...)

 

[2hawk]

This should help...

 

[BELT_FED]

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

 

[BeginingOfTheEnd]

Been wondering that myself.

 

[chuck s]

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

 

[shawnr5]

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.

 

[ledman]

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.

 

[DavidRSA]

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)??

 

[chuck s]

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

 

[ChattanoogaPhil]

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.

-- 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.

 

[ledman]

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.

 

[DavidRSA]

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.

 

[traindriver]

M&P 15-22 Receiver Extension Size??

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

 

[scootle]

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

http://smith-wessonforum.com/smith-...sed-about-buffer-tube-commercial-milspec.html

must be the night for stock-shopping.

good luck! (and welcome to the forums!)

 

[glockeyed]

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

 

[shawnr5]

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.

 

[scanner]

yes milspec

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

 

[Hattrick23]

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?

 

[pullinmapuddah]

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?

 

[CrazyFingers]

I have a m&p 15 sport and bought a Magpul ACS mil spec stock to replace the factory one.

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.