I like the idea of the palmsaver on the side of the tube (but I suspect it's not strong enough for a tight loading sabot), but the caps do not seal securely......at all. I wouldn't trust them to hold the powder without spilling it everywhere. And the little plastic tabs that attach the caps to the tube stick out like loops...just begging to get snagged and pop the loose lids off.
Anyway....worst speed loaders ever. Just saying. They might be OK for pellets.
I'll probably be too lazy to bother sending them back, but I should as a matter of principle.