I just bought a Magpul PRS SR25/M110 stock and realized that I needed to change out the buffer tube. My question is that if I buy this tube:


will the spring and plunger need to be replaced too or do I just need that tube to install the PRS stock?

I'm confused by the whole A1/A2 buffer tube and mil spec tubes. I understand that mil spec and commercial are different but does A1/A2 = mil spec?

Read this: Magpul PRS

A1 and/or A2 refers to the length of buttstock. Both use the same buffer tube and buffer/spring. The difference is that the A2 has a plastic spacer and the longer A2 stock.
You do not say which tube/spring/buffer you have now but since you are buying the tube you may not have the spring or buffer you need either...maybe a better way of saying it is: if you have the correct buffer and spring why are you buying a tube???? Typically they all three go together as any other combo don't work.
If you are building from scratch then you need the tube, then you need a rifle buffer and spring {as opposed to the carbine or shorter buffer and spring.}

Oops, sorry, I should have clarified for you the "mil-spec" nomenclature...that refers to the carbine or collapsible type tube and buttstock. The mil-spec collapsible stock tube is smaller in diameter than the aftermarket ones. You can place the aftermarket stock onto the mil-spec buffer tube, but it will shake and be a sloppy fit. You cannot put the mil-spec carbine collapsible stock onto the aftermarket buffer tube. To the absolute best of my knowledge all rifle buffer tubes are the same diameter.

"More Information:

The PRS is a direct replacement for an A1 or A2 fixed stock.

Fitting to a Carbine will require a Rifle Receiver Extension tube, Rifle Buffer and Spring (not included).

Mounts to Rifle Receiver Extension tube without A2 Spacer."

IF a person is talking about a S&W MP-10 with a (factory installed) collapsible carbine stock, and wants to install a A2 stock OR a Magpul PRS, a mil-spec A2 buffer tube will thread into your MP-10 receiver. They are the SAME diameter and thread. How do I know? I have put a A2 buffer tube and A2 stock on an MP-10