mxpatriot51

Both work. Doesn't hurt to get the M4 cuts. Just make sure the upper receiver and barrel are for the same cut. M4 cuts require a receiver cut for M4 cuts to be reliable.

1. Wrong. You cannot have a pistol grip AND a folding stock on a semi-automatic shotgun. A pistol grip with a fixed stock is fine on a semi-auto. What the OP has to worry about is making sure he has enough U.S. made compliance parts to comply with 922R when he starts swapping parts and extending tubes. And to the OP, 18.5'' is way too short for open. Your magazine tube will be a mile in front of your barrel.

Going to put a tube on my new Benelli 21'' M2 to get it up to 8+1 for tactical class and trying to decide on which tube I want to put on it. So, which tube do you run, which one would you buy (if different than what you're running now), and why?

Trust me, don't buy the Remington. I bought an 1100 Tac 4 (22'') to use for three gun. It ran fine out of the box. Added a DMW's easy loader. Shotgun still functioned fine. Fast forward a few months. Now all of a sudden it would not cycle slugs HALF of the time; meaning on one stage it would be 100% with slugs and on the next it'd be a single shot slug gun (wouldn't even eject the empty slug). Then it started malfunctioning with birdshot. I tried different loads, cleaned the hell out of it, even opened up the gas ports. Finally got it back to cycling birdshot, but it would not lock back when empty when fired; but would lock back when empty when the bolt was manually pulled back. I finally decided "ENOUGH!", sold it, and bought a Benelli M2. I would've saved a lot of money had I just bought the Benelli first.