Slugster, get the wally world one. I'ts the mossberg brand barrel, ported and cantilever scope mount. I have that same barrel on my 12ga and it does VERY well with cheap ammo. Remember that once you go to a rifled barrel you will not be using punkin balls anymore. You are stepping up to sabots and the price just quadrupled on the ammo.
I shot lightfield slugs until they went up in price to 15 a box. I now shoot hastings at 10 or lower. I am still trying to get a group buy worked out with hastings for a BUNCH of slugs for all us allegheny county guys that shoot them. Might be about 8 bucks a box when the dust settles.