I've been looking to get the Dominion Arms Grizzly 8.5 Magfed Shotgun from Canada ammo. But I was curious if the 8.5 in. barrel can be swapped out for a longer one when I'm not backpacking/camping. Would like to also be able to use it for hunting and what not. I heard the 12.5 in. is fully compatible with 870 parts but the 8.5 in. tube mag isn't. Would the mag fed version be different??