Don't exceed 100 grains powder & 400 grain conical combination. I would imagine that 90 grains powder & the 405 Powerbelt would meet CVA's standards. You can use 100 grains of powder with the 348 Powerbelt... which is classified as a conical. There is no sense in using magnum powder charges with Powerbelts anyways.... in most cases... they shoot lousy target groups with their thin gas checks or even entirely blow the gas checks with hot & heavy 777 powder charges.