What size buttstock do I need for my Mossberg MMR? Commercial or Milspec?

[sgt.rock]

I do not know what kind of buttstock to get for my AR15. I am not a fan of the fixed A2 style that it came with. I want an adjustable length one. What do I buy?
How do you know what type of tube is equipped on the gun? Here is a picture of the buffer tube.



I think it is Mil-spec but what do I know?

 

[P0WERWAGON]

it is neither. milspec and commercial are the terms for the shorter adjustable stocks. you have a regular A1 buffer tube that has a small plastic spacer to fit the A2 stock. a PRS stock fit that tube.

the stock you get should list what is it and usually come with the tube buffer and spring. if it doesnt, after you buy the stock, then you will need to buy the type of tube you need, along with the buffer and spring.