welcome nick,

i don't think you'll have any trouble acheiving MOS accuracy to 50 yards. there have been a lot of targets posted here (search accuracy).

just out of curiosity, why do you want to put a fixed A2 stock on the rifle? if it's for stability, just pin your fixed stock. in any event, i don't think you can mount a standard fixed stock because the "buffer tube" is solid so you can't screw the stock in without some modification. for what it's worth, i've got a magpul ctr on mine and it's really solid, much better than the OE collaspible.

my 2 cents, get one with a flash hider if you decide to get one. good luck!