Magpul CTR Mil-Spec vs. Commercial??

[Hyprlite2007]

I want to get the CTR buttstock but I dont know what the difference between the Mil-spec and Commercial versions are..

[Beebo]

Here is a link to Magpul's website that has a .pdf that can help you determine which size stock you need to get.

http://www.magpul.com/tech/ctr.html

Hope this helps.

[Hyprlite2007]

Here is a link to Magpul's website that has a .pdf that can help you determine which size stock you need to get.

http://www.magpul.com/tech/ctr.html

Hope this helps.

Perfect, thanks a lot!

[Beebo]

Not a problem. Enjoy the CTR. I have two and enjoy them quite a bit.

[Armadillo]

Is one better than the other?

Assuming that Mil-Spec came out first, how did commercial come about?

[kaiservontexas]

I guess the commercial came about because many AR-15 rifles have commercial tubes, example a Bushmaster rifle. People like MagPul products and MagPul wants to make sure they can offer their product to those individuals.

[wake.joe]

I switched over to a Commercial tube, because it was the only CTR I could find at the time. :D

When I find a MilSpec stock, I'll switch back. But I haven't gone out of my way to find one.

[FJ540MN]

What brought about the commercial size variance though?

Seems dumb for a manufacturer to go out of their way to make a different tube diameter just big enough so that mil spec parts won't work on their guns.

[Hound_va]

Think cheaper, easier to machine materials, fewer machining operations, etc;. 6061 is used instead of the spec 7075 as part of the same cost cutting measures. If it looks the same, who would possibly know the difference? :rolleyes:

[rob_s]

No tubes are truly "milspec" unless they are forged and from the proper grade of aluminum, although the terms are now pretty much used just to refer to the diameter, which is why I list the diameters on The Chart.

milspec tubes have threads which stand "proud" of the tube which is more expensive to manufacture when you're extruding instead of forging. In my research Colt is the only one that forges their receiver extensions. there are also two types of aluminum used, just for the record. Frankly, given that they are both extruded and both made of the higher quality aluminum, it makes no difference if you've got a 1.148" "milspec" tube or a 1.68" "commercial" tube. some argue that the thicker material of the commercial is actually better, while others argue that the typically "flattop" threads of the commercial is weaker than the engagement of the sharp threads on the milspec.

I use all 1.148" tubes even when they aren't from Colt simply for standardization purposes across my various rifles, and because there are, and have been, stocks made that didn't come in 1.168" size.

[FJ540MN]

I didn't realize the commercial tubes cut the corners like that. Proper thread profile is important, but proper material strength is even more important.

The root of the threads is going to be the same on either one due to having to fit in the same threaded hole. Having a thicker outer diameter OD to compensate for a weaker material is idiotic as the ID remains the same and your thread minor diameter OD will remain the same. The weak point will be the junction of the threads to the regular OD just past the extension nut.