RE: which shotgun?
With 400 dollars for a shotgun id........
For upland game id go with an 870 wingmaster.
For waterfowl id go with an 870 sps super mag.
There aint nothin wrong with a good pump shotgun.
400 is too little to spend to get a good autoloader. The remington's are pretty good, i own two of them (11-87 20 gauge, (11-87 sps super mag). Theyll run you about 600 at the cheapest probably. The benellis are awesome, I have one (super black eagle). Thatll probly cost ya about a grand.