As an owner of both I can only saw "not much"..and the difference is really not worth arguing about..I use the Federal 3 in 2 oz heavyweights in #5 for turkey, the same thing for 3 1/2 except it's 2 1/4 ounces, no gobbler has ever walking away from being hit with either.. personally I prefer the 2 oz 3 in, the extra bang, noise, expense and without question recoil..not really sure it's worth it to be honest about it.....