Does anyone know the M&P 10 (18") barrel diameter at the thin portion between the gas block and the flared end? Looks to be .750 at the gas block and probably the same at the flared end and the threads for the hider are 5/8"x 24 I believe...
Wondering about cutting the barrel back to 16" and still being able to tread it to 5/8.

Appreciate and help!

-J

Depends on what barrel you have,,,,is it 20"/ 18"? if its a rifle gas length, and depending on who made the barrel I am pretty sure you could do that. Are you going to do it yourself, or have someone else do it? --Rob

The only model with a flared end and flash hider is the 18", but I edit the original post anyway, should've specified.
Have a smith to do the work.

-J

If as you say its .750 at the gas port area, I am fairly certain you will not have a problem getting the 5/8x24 threads at all. Should be a nice looking AR10

That's the thing... its not .750 where you'd cut the 18" model down to 16". As you've probably seen its .750 at the block then tapers down till the flared end of the barrel.

-J

My 18" M&P 10 measures .600 where it would be cut to 16". You could thread it 5/8-24 in this area but you would be missing half of the thread engagement. that just wouldn't work unless you silver brazed the muzzle device on. an alternative would be a muzzle device designed for the 6.8 SPC which is threaded 9/16-24. You would have a lip for the crush washer of only .020" per side this would catch a crush washer bored out to .562 the entire operation needs to be professionally done and there are many "gunsmiths" out there who would surely screw this up.

Much thanks rlowe!

Any chance you could help me with a few other measurements? I have another post titled "Measurement Help??"

Thanks again!

-J