Benelli M1, M2 and M3

New to the shotgun area.

What are the differences between M1, M2 and M3?

Thank you in advance.

[imported_kantstudien]

Never heard of an M2, but the M1 is a semiauto while the M3 is convertible between semi and pump action for low recoil rounds which won't cycle a semi. The M4 is the latest style semiauto with collapsing stock (in free states).

[USCG1988]

detailed info ont he M2 can be found here:

http://www.benelliusa.com/firearms/m2.tpl

USCG