Different rifles, different fixes.
Barbara & I got identical M-4's about a year and a half ago.
Barbara's AR shot 1" groups right from the box. Mine was about 2" groups.
I freefloated the barrel and put a match single stage trigger in mine. & it went to about 1/2" MOA.
It got better about 500 rounds down the tube too.
I guess I like the freefloat tubes and what they have done for AR's.
Something about that plastic stock bolted around the middle of a barrel just gives me the willies. (Like the Mini 14 as well.)
To answer your question, I agree with NcWhitetail.
I never shoot any of my rifles off of anything with the barrel touching anything....Sandbags, shooting sticks, trees, etc. In my opinion, that messes the harmonics of the barrel up.
Barry