Use slugs in your Mossberg. Save the money.
With a slug barrel. Good idea.
Every deer (except the ones I hit with a car) I took with a 12 Gauge Mossberg 500. I think it's much more of a chalenge than dropping a deer from 400 yds. away. Not to take away from that 'cause that takes a great deal of skill as well. I guess it's what you're used to. I hunted in Ohio where shotguns were mandatory. Now that I live in Pennsylvania where I can hunt with a rifle I no longer have the urge.