I shoot a Mossberg 835 and absolutely LOVE IT. Like MKMGOBL said, it kicks like a mule! I use a Primos Jellyhead choke tube and have excellent results with it. Remember, when buying a choke tube for Hevi-Shot, the choke tube HAS to be compatible with it. Some arent, so you have to make sure.
I used to use Winchester Supreme Double-X Mags, 3.5" #5's and had good results. But, a member on here and I had several discussions about Nitro Company shells. He kept urging me to buy some but I just couldnt do it. Well, I finally got talked into buying some and he was 100% right - NOTHING beats them. Do you have to have them to kill a turkey? Absolutely not. But, in my gun, NOTHING comes even close to comparing to a Nitro.
Good luck!