There's a rule of thumb on going from plastic wad loads to nitro cards and fiber wads to increase the load by 15% to make up for the inefficiency of the old wads. I wouldn't bet my old guns on that rule of thumb without testing. I had issues with inconsistent velocities with NC and fiber wads. I haven't given up on them. The small plastic gas seal from BP was a sanity preserver. I was trying to develop loads for a 2" 12 ga. I had wild swings in velocity with the old school approach. I abandoned testing in the double and shot them out of an 870 to chrono. The gas seal brought everything closer in speed. Until I can come up with a load in NC and fiber, that's what'll it'll have to be. It may have been inconsistent seating pressure, but there's a school of thought that isn't an issue. Gil
