Mil-Spec vs. Commercial Diameter Buffer Tube ??

[billt]

Is Colt the only manufacturer that uses Mil-Spec Buffer tubes? I ask because I'm thinking of going to the Vltor E-Mod Buttstock on my Bushmaster and Colt AR-15's. They came stock on my LWRC guns, and I really like the way they fit and feel. I don't want to replace the buffer tubes, springs, or Castle Nuts. I'm looking for a nice, easy off / on installation. No muss, no fuss, no cuss. I'm almost positive the Colts, (6920 & 6940 Monolith LEO Carbines), are Mil-Spec diameter tubes, and the Bushy's are Commercial diameter. I just wondered if there is a list of the different manufacturers, along with what size buffer tubes they use?

I was also thinking of going with one on my Rock River Arms LAR-9, 9 MM carbine, but I have no idea what they use on the 9 MM weapons, or if even Vltor makes one that would fit?? Also who has the best deals going on these things?

[fightingquaker13]

Try the AR15 armory.com. They are friendly and helpful folks. The general AR thread will get you your answers.
FQ13

[Dakotaranger]

I'd tell you to measure the end of the tube because Mag-Pul lists the differing sizes between the two on the website, but I can't tell the difference.  The best bet is just to call Bushmaster up and ask.

[twyacht]

Amazon sells a gauge from Tactical Intent for like $1 or $2...

LMT, LWRC, Stag, M&P (Stag Clone), POF, Armalite, are all mil-spec lower receivers. DPMS, are commercial although they have done a great job confusing things now offering a mil-spec version..

I have heard Bushmaster's have both?

Not sure of Ruger, Olympic, and Para AR's,...quick call or google fu, may confirm, if someone doesn't already know (bafsu?)

The buffer, spring, and castle nut are all the same.

Put a caliper or real good tale of the tape, to check.

I have the VLTOR EMOD, mil specific, and it went on my mil-spec tube like a glove.

Good question,...and one that is important to avoid the wubble.... in picking a stock.

[blackwolfe]

I believe that Rock River uses commercial spec tubes on most of theirs.

A few more details on measurements from this magpul link:

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

[Sponsor]

[billt]

Thanks T.W. & Blackwolfe

[billt]

On my Bushmaster M-4 A-1, the Buffer Tube measures 1.165" about halfway out where the stock slides over it. But right in where it screws into the lower it measures 1.145". So I'm guessing I would need a Commercial Vltor E-Mod Stock, not a Mil-Spec?

[twyacht]

You are correct billt.

According to AR15.com,....Bushmaster is 99.9% Commercial tubed.

http://www.ar15.com/forums/t_3_12/442122_RE__Bushmaster_buffer_tube_mil_spec_or_commercial__.html

I also called my Black Rifle guy here at Guntech, Ft. Laud, and he confirmed standard Bushy tubes are indeed Commercial.

Don't forget a picture when you get the new stock...

[blackwolfe]

Bill, I think Bravo Company might have somw specials on Vltor stocks right now.

[bafsu92]

The easiest way to tell if your tube is commercial or mil-spec is to pull off your stock and look at the end of it. No need to measure diameter etc. If you look at the drawings that twyacht provided you can see that mil-spec tubes are flat/square on the end where commercial tubes have a slight angle. Also a commercial stock will fit on a mil-spec tube with a little slop but a mil-spec stock will never go on a commercial tube. Quite a few manufacturers use mil-spec besides Colt, Noveske, LMT, BCM and LaRue come to mind but I know there are others. The mil-spec tube is really a cheap upgrade since it's made from a much heavier gauge, thicker walled material than the commercial tubes. Thinner diameter and much thicker wall, lots more strength for $30-$40.