I have a smith and Wesson m&p 15 sport(.556). It's carbine length. I really like the magpul PRS stock, how do I go about changing the buffer tube and buffer spring to fit this stock. It's my understanding that this stock is for fixed A1/A2 stocks. I know I'll have to buy the A2 buffer tube and spring, as well as some sort of receiver spacer? Help anyone? Has anyone done this to their AR?

I would absolutely not recommend the PRS stock on your Sport. It is heavy, and built for precision shooting, with most applications geared towards MK12's, 18" barrels and up. If you are intent on dropping $250 on a stock, you would have to swap out your stock with a Rifle length buffer, buffer tube, and spring. You don't need a spacer (unless I'm mistaken).......they sell the rifle length gear at Midway, and will run you around $50.

I went with the Magpul CTR stock on my sport and love it

You'd need to swap out your carbine buffer tube, spring, and buffer for the fixed-stock rifle counterparts. Peen back the staking on the castle nut. Remove castle nut. Remove buffer tube. When removing the castle nut, make sure to release the buffer tube plate slowly. It retains the spring and detent for the rear pin. When removing the buffer tube, put your finger on the buffer retaining pin. It's spring loaded and can fly out.

Install the rifle parts.

IMO, you want to put on a PRS stock go for it. Post pics.

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-John

B5 stock here. Nice cheek weld and nice rubber pad on back stays put.

I went with the CTR from Magpul. I like it but I changed out the buttpad to the extended version for better placement on my shoulder. I would either go with a Hogue, MFT or STR if I had to do it over again.

If you are looking for a fixed stock try the Magpul Fixed Carbine stock with the extended buttpad. No changes to existing parts and you have a solid system. ALG Defense ACT trigger is the best 64 buck trigger around.