[What are the differences between M2/M3 and M4?]

Thanks for all the advice - this site has some folks who know their shotguns.

 

I'm still looking at them (on-line) - no place local to see them (N. Idaho). Does anyone know which one (m2 vs m4) will cycle faster?

[What are the differences between M2/M3 and M4?]

I've been looking at these shotguns for home defense and am trying to get a handle on what are the differences between the m2/m3 & m4. I've noticed the M4 appears to be more expensive, but looking at them online I can't figure out what is different.

 

thanks...rick