Any reason to choose commercial or mil spec buffer tube diameters?

[Tim K]

Is there some compelling reason to choose one over the other?

[KS63]

I'm thinking mostly for more stock options.

[Circuits]

There's no functional or material difference between commercial receiver extensions and most of the "milspec" receiver extensions out there. Just the same cheap extrusions in a "milspec" diameter.

For durability, a true milspec receiver extension is a different thing altogether - though most of us aren't going to subject our rifles to a milspec-requiring level of use and abuse.

The "milspec" diameter does offer more options for choosing stock bodies, and the cheap ones cost no more than the commercial diameter.

[Robb]

If you're not jumping into Afganistan anytime soon, then no reason for one over the other unless you just want to own 'the best'.
I did research on this a while back.
A true mil-spec tube is a 7075 extrusion, which is stronger than a commercial tube. Commercials are made from 6061 extrusions, many tubes will say something like 'Mil-spec diameter' but be 6061.
I have one COLT buffer tube, it's supposed to be hammer forged 7075-T6, and is glass smooth on the inside, nice stuff. Colts are insanely priced but BCM and Palmetto offered one they advertised as 7075 hammer forged in the past and probably still do. I'm sure others manufacture them also. So there is a difference, it's just probably not worth the extra expense for most people.

[Tim K]

I have one in commercial already, so I think I'll just continue that direction. That way I can swap stocks around if necessary.