I've been shooting the A400 the past 2 seasons from dove's to snow geese and here's my feedback & troubles of the gun that as we know cost's a bit of $$$$
1st shotgun: Had it for about a month or 2 and developed trouble with it cycling 3.5" shells on a consistent basis. And than on one hunt, the magazine cap blew in 2 pieces. Took it make to the dealer and got a new one.
2nd shotgun: Had it for the rest of the 12-13 season and it too had trouble with cycling 3.5" shells on a consistent basis so took that one make to the dealer and got a new one.
3rd shotgun: Same situation with the 3.5" shells last spring while snow goose hunting so send it back into Beretta over the summer. They updated the forearm, adjusted the carrier and added oil to the bolt assembly. Though out last fall, didn't have a single issue with the gun shooting 3.5" shells until the last wknd of goose season when it wouldn't cycle them on 2 volleys (-25 wind chill) but that was also the same day that the magazine cap broke in 2. I put my old Xtrema2 cap on it and it shot fine the rest of the season.
Any of the 3 shotguns I've had have no issues with 3" shells and not a single mishap with those or smaller shells when dove hunting.
Henkiller is the only other owner that I've known that has that mag cap break off other then the dealer telling me they had one case of the broken cap. I'd say the guns not liking 3.5" shells is more common from what I've read/got messaged about over on the refuge forums. My current A400 is in the 80,000 range as far as serial # so not sure what #'s they are now to have gotten the bugs out of em.
If I was purchasing a new shotgun right now, I'd be alittle hesitant to get a A400 because if you happen to get a bad one, you will be frustrated. But if you get a good one, it's a light's out shotgun as it's soft recoil and shoots very fast. Mine was great thought this season until the mag cap broke off.
I believe mine has been fixed and though the whole mess, Scheels has been great for me!