I used one for a season, as a field gun, here in KS hunting over pointers.
It was 16ga with 28" poly-choked smooth barrel, believe all my shells were 2&3/4" with 1oz shot.
When I shouldered A5/M11's previously, either at store, or handling friend's guns, I always seemed to be staring at that hump.
But when I got in the field, walked up behind my dogs, and flushed birds...it really worked well.
First bird hunter error is shooting behind birds, second is not putting your head on the stock.
That stock/receiver seemed to be a benefit in the field, slightly more heads up mounting. I shot it very very well as a field gun.
Never shot it on skeet field or any clay targets for that matter. Does have sufficient mass to maintain good follow through.
Did not have any functional issues, shooting standard velocity 2&3/4" 1oz shells.
All of my shotguns are either fixed breech or pump action, so that M11 sounded like quite the "contraption" when it fired and all that finely fit US steel started shucking & jiving.
