my understanding is the M&P 10 is neither an AR-10 nor technically an LR-308 layout but something in between. however for parts like pistol grip, stocks, forends none of that should matter. in general when you get into 308 AR platforms one finds a whole lot more variability but everything is work-able. you should have no problem swapping your furniture on that rifle. if you're dicking around with the upper might as well free-float that barrel and install an adjustable gas block. these rifles are awfully over-gassed. it should have a rifle length receiver extension tube. if not that would be another upgrade I would be doing. then go with a rifle length stock like the magpul MOE whatever you like.
Pistol grips and buttstocks and sights are about the only thing that is compatible. The gas system is a carbine Or midlength + 2" i believe. Which is nonstandard. Charging handle is non standard. And everything else internal is non standard. But like most , AR10s do not have a universal standard.
AERO, and Savage might have the traditional parts compatibility.
why does everyone have to refer to .30 cal AR pattern rifles as AR-10. they are not. the S&W is not armalite pattern. if there's so much confusion about how to build or modify a rifle then call S&W and let them advise. all of these rifles are modify-able if one learns them.
A little help: Given the proprietary nature of my S&W M&P10, I'd love to have an extra complete upper w barrel, for when mine wears down. Does anyone have specifics on how I could accomplish that? The uppers, last I checked, are not sold by S&W, which, at a glance, almost makes the guns disposable. Love mine, by the way.
I have an MP10, and it appears you can switch to a DPMS standard barrel, but you have to also switch the BCG. If you do both then you will have no issues. Stock BCG and barrel are proprietary, but both can be swapped out. Note, I have not tried this, but it's simply what I found in my search. Have spent hours looking into new trigger options.