Some invector+ barrels shoot a lot better with a .670 to .675 constriction, my 26" SX3 didn't do as good with.675 and really likes the IC.665, I'm getting 280 to 310 with Hevi 13 2.25 oz. #7,lot # 300325 and 300326. I've got a .675 kicks and Supermax so I'm not comparing apples to apples either.The .675 IC may out shoot my IC .665 but I'm happy with it.