I have the Mossberg SA 28 turkey, and it is just as deadly as any of my 20 ga guns. The 28 ga 2 3/4 hull can be loaded with 1 5/8 oz of tss.. same as a 20 ga load. I have been hand loading and have settled on a 1.5 oz load. It puts around 250 pellets in 10" at 40yrds.. with a good even 20" pattern.
Needless to say, it has moved to my number one turkey gun.