As Ky said, use the shorter wad. I've been doing this for 10 years or so. I called CBers and ask about subbing in a shorter wad. He said, unofficially, if the only difference was the cushion area, at low pressures he wouldn't be afraid to do it himself. Contact the powder companies and they'll send you a reloaders booklet for free. Then you can easily compare different loads. You can use the 2 3/4 data in the 2 1/2 shell, you just have to make it fit. Like with a shorter wad. At the pressures guys have listed I wouldn't worry about subbing in a wad and the pressures being too high. I've never sent one in for pressure testing yet, but to each their own.
