Then how do you load a light target load? With a .38 and a 148 grain wad cutter, you only need 2.7 grains of Bullseye. That's about a third of the case volume.
Usually, if you're compacting the powder, you've accidently double charged the case, and it will go boom. If you're working up a compressed load intentionally, that's a different matter.
“Then how do you load a light target load? With a .38 and a 148 grain wad cutter, you only need 2.7 grains of Bullseye. That’s about a third of the case volume.”
I hear what you’re saying. The fast double-based powders like Bullseye and Unique have been around a very long time and seem less prone to low density detonation than some other powders. Some reloaders even fire form new rifle brass using squib loads of the stuff. Reloaders for cowboy action shooting load for low velocity (pistol 700-800 fps) and often use bulky powders like “Trail Boss” to prevent accidental double loads. That should work well for target shooting.
With pistol powders, the problem isn’t as apparent. Pistol powders are already fast burning. The issue really arises with rifle powders because you’re effectively changing (increasing) the burn rate by igniting such a wide swath of the powder stack.
Some of the new rifle powders are very slow burning by comparison to pistol powders. In a .223, the issue might not manifest itself in overpressures high enough to cause chamber failure, but in large capacity magnums of .30 cal and up, I’ve seen more than one case failure and one stuck bolt from a “light target load” that filled only perhaps half of the case capacity.
The meta-issue is what you’re effectively doing to the burn rate of the powder.