I'm building a DPMS patterned 308 rifle (Yes, even here in California we can build these) and have a question on buffer tubes.

I bought a Magpul PRS (2nd generation) buttstock and need to get the buffer tube for it. Does this stock take the commercial or MilSpec size buffer tube?

Fjold, I don't know the answer to your question; but you should be able to email the folks at MagPul to get it. I am very happy to see you bought an excellent lower ! I bought two of their AR10 lowers and am very happy with them. I will say, however, you should get a RR match trigger for it. I love the "beefyness" of the lower and how well it mates up with my uppers. So far, my 260 Rem. is shooting under 1/2 " groups with it. Good luck with your build and I hope you get your answer.Charles

I could be wrong, but IIRC both the DPMS and Rock River use proprietary sizes....and on the barrel nut as well.

I would hop on AFRCOM to find out for sure....and go with a SLASH buffer spring.

WOODNUT: Sorry, but there is only one AR-10 and it's an Armalite.

I begg to differ (AR10comment). I own a DPMS SASS and it will shoot 3/4inch all day long. Sub MOA from a production rifle is pretty good.

Irregardless of how tiny a group it shoots...it's still not an AR-10.

And my comment is not to bash DPMS...merely a fact that only Armalite is AR-10.

A Mil Spec buffer tube has a diameter of 1.148” while a commercial buffer tube has a diameter of 1.168”.
Take a set of dial calipers and measure the inside diameter of your stock. The stock will be roughly .010” larger than the buffer tube it was designed to fit.