Re: forming 280 ai cases
I have a 6.5x280 Ackley. Cases are formed by necking down standard 280 brass to 0.264, loading a standard load, not a light one, and shooting. No need to have bullet contacting lands. You will want to use a fairly stiff charge, like medium to maximum standard 280 loads, to fireform. You will have to play with this a bit to get nice sharp shoulders on your cases. I have found Norma brass to be the best available. Win makes only nickel plated for the 280. I have also formed cases from 270 win brass (in the 6.5) by forming a false shoulder a la Gibbs. This gave me a better case to chamber fit. Lately though I have been using the Norma 280 brass with good results. It isn't cheap though.