While that is true that most BPI barrels are suited to shoot the Powerbelts, many of the other rifles although not intentionally are made to, will also shoot Powerbelts very well. A lot of it I am sure depends on the barrels. Also if you shoot and fowl some of your rifles as many do in their first shots. they then find that without swabbing, the Powerbelts make an excellent accuracy, fast loading second shot. All you can do is try your rifle and see how they like Powerbelts.