From what I have seen to reach that 50 yard or beyond mark you really need a dedicated turkey gun. My buddy has a remington special purpose with a super full choke in the 3 1/2 inch. His is good out to around 60 yards if you hold over a bit. The down side is if you shoot at anything under 30 yards it shoots like a slug gun! I have another buddy that has a mossberg with the back bored barrel and it works pretty well too.
I had a mossberg 500 bantam with the 12 ga ported barrel. It was good to around 40 yards with an extra full extended turkey choke. I think it was a hastings, not sure though. I had fiber optic adjustable sights on mine as well.
What I learned is you HAVE to try different types of loads, just like a rifle. Try a few different brands and different types of shot sizes. #6's were not worth a darn in mine, very inconsistant pattern. I finnally ended up using winchester 3 inch mag 2 oz turkey loads with #4 shot. I always seem to have good luck with winchester ammunition.
I also found out it shot awsome with 7 1/2 field loads, too bad they are not legal for turkeys and probably don't have enough power kill one beyond 20 yards

. Did a number on pesky black birds though

.
Too bad I traded my mossberg in on my slug gun. Now I just got a new NEF pump gun and need to start all over again.
Paul