i also have a mossberg 500 12 ga. I had the remington 870 ultra mag combo that shot 3.5s but i had a lot of problems with it, the shell always got stuck in the chamber and wouldnt eject. tried different shells, still did it. So i sent it in, they said they fixed it and it still did it so i took it back and got the moss. and i love it. Maybe i just got a bad remington i dont know but i really like the mossberg 500. Came with a slug and smotth bore barrel for about 4-500. I use that for everything.