Some thoughts for discussion:
All current domestic 20 Gauge buckshot cartridgess use a gas seal, filler wad and buffer. That's right, no shot cup.
And considering current #1B offerings in other gauges run to pellets of .285" diameter, it seems a change to #1B in the 20 bore be a welcome industry change. The current crop of #3 and #2 buck could be discontinued - eliminating two pellet sizes from industry inventory. Then, still using gas seal, filler wad and buffer, 12 pellets in 2.75" and 15 pellets in 3" 20 gauge shells could be marketed with these 33 grain pellets loaded in slightly loose stacks of 3 pellets per layer.
All current domestic 20 Gauge buckshot cartridgess use a gas seal, filler wad and buffer. That's right, no shot cup.
And considering current #1B offerings in other gauges run to pellets of .285" diameter, it seems a change to #1B in the 20 bore be a welcome industry change. The current crop of #3 and #2 buck could be discontinued - eliminating two pellet sizes from industry inventory. Then, still using gas seal, filler wad and buffer, 12 pellets in 2.75" and 15 pellets in 3" 20 gauge shells could be marketed with these 33 grain pellets loaded in slightly loose stacks of 3 pellets per layer.