As far as I am concerned, Benelli really screwed up a good thing with the M2. Otherwise the rest of the mechanics are the same. Time will tell how long the block will last. The trigger group block is now plastic, with a smaller, hard to reach safety button. Not very strong and will probably get bent if you throw down the gun wrong when you need to ground it in a hurry. Other things I don't like about the M2 the fent rib has been changed to a much lighter, fewer posts and thinner design. Nothing better then a Sims Limbsaver can do on a M1 stock. The M2's 'ComforTech' stock has way too much marketing hype stuck to it. The M1 stock can be shaped to fit the M2 receiver. The M2 receiver has been recontoured mostly at the rear where the butt stock meets it, so the shape of the M2 stock will not match the M1 without corners of the receiver exposed. The M2 forearm will fit the M1 barrel, but the M1 forearm will need some slight modifications to fit the M2 barrel, (easy to do). The M2 barrel will fit the M1 receiver, (and vice versa). The Benelli M2 is a warmed over bastardized verson for the M1.