I think i'll go with the Federal Tru-Ball they're price isn't bad and I can find them on the shelf easier than Brenneke slugs, and heard really good things. also I did have a rifled barrel when I first bought my Mossberg 500 combo was excited about using it but when I found out how much those sabots cost I sold the barrel to get a scope for my muzzleloader, I realized I didn't really need a rifled barrel I hunt in very thick woods and was very tight on cash so I bought just regular Remington slugs got a total of 3 deer in two years with the Mossberg, I'll get a couple of different types of ammo and see whats best.
Thanks