Just a quick report from the range earlier this week.
Loaded 40 grains Blue Dot + X12X gas seal + 1/2" fiber card + 1/8" felt + 1/8" Nitro Card, and roll crimped by feel with a hand drill (the rounds previously pictured.
Chrono reported
1322
1306
1266
1280
1304
1310
These certainly feel as Thumperish as I need to go for now. I'm going to borrow a drill press and crank out a batch of 40 or so with consistent roll crimps, and maybe get a few sent off for pressure testing.