Question for M Koneski-8ga reloading

[Craig Larter]

One think I have learned is the material used to take up stack height makes a difference in pressure. In one load I used four 1/8" 10ga nitro cards as filler, in another, the same except I used a 1/2" fiber wad. The nitro card load averaged 8200PSI, the fiber wad load average 6833psi. Velocities were similar at 1130fps. It must be that the fiber wad is softer and compresses on ignition.