I have a 20" Mossberg MMR that I really like too. Flattop plus 20" barrel. 460 rounds so far (bought used) and not a single stoppage. (only ran a boresnake through it 2x)
I find the "recoil" from an AR is more from the Bolt carrier group moving back and forth, disturbing the balance of the gun, than any actual rearward force from the round going off.