Re: Benelli M3
To the OP.
You said Tactical and 3Gun, so I can just address the 3 gun.
I have an M3 and like it very much. However, do not count on the pump mechanism as an avenue for jam clearance. In the rare event of a jam, you would be much better served by attacking the problem in the normal manner as opposed to farting around with the pump, so I do not see that as an advantage. Both a positive and negative of the M3 is it has added weight (vs the M1/M2) due to the pump mechanism, which help attenuate recoil, but ...... it is added weight. Also, a negative on the M3 is that it has a max of a 7 round tube, and for most 3 Gun you can load 8, so that is a disadvantage. If there is an aftermarket tube for the M3 I have not found it.
The M4 is a gas assisted shotgun, as it has the normal inertia driven mechanisam of a Benelli plus the gas to make sure it will cycle. However, I have shot a couple of M4's and would not recommend them over the M1/M2 for 3 Gun due to the added weight, and to me added perceived recoil, and the lack of aftermarket accessories such as extended tubes.
So, for three gun, all things being equal, if you are going out to get a new shotty, look for an M1/M2 with a 21 inch barrel. Its the shizzle.
Thoughts from here.