Found another powder that works with small primers in plastic and RMC cases, w/600gr slug. It is IMR 4227. Ignition perfect, same load levels and velocities as 4759.
Powders slower than shotgun type, that ignite properly with small primers(shotgun-lg rifle); we found 4759, VV-110, 4227, 7383 surplus, the latter a slow powder that also works with real heavy slugs Ed