Receiver extensions – mil spec or commercial?

[chp5]

Do the following lowers take mil spec or commercial receiver extensions:

• Stag
• Mega

Thanks.

[Robb Jensen]

Lowers can take mil-spec or commercial receiver extensions.

[chp5]

Lowers can take mil-spec or commercial receiver extensions.

Thanks - here's a better question:

How can tell whether I have mil spec or commercial receiver extentison?

[Robb Jensen]

Thanks - here's a better question:

How can tell whether I have mil spec or commercial receiver extentison?

When their off of the lowers the mil spec receiver extension threads will be actually bigger than the outer dimensions of the body of the tube. The commercial tubes threads will be at the same diameter as the body of the tube.

[8200rpm]

Mil-spec:

http://www.magpul.com/pdfs/buffertube-Milspec-M4.pdf

Commercial:

http://www.magpul.com/pdfs/buffertube-civilian-M4.pdf