Back in the 70's I had a Remington sold Italian Zouave .58 for which I bored the noses of the minnies out on. My 505gr. mould cast oversize, right at .580", so I modified the plunger and made them almost solid with a very short thick skirt. They came out at 600gr.+ - I do not remember exactly. I would bore out the noses, roughly 3/8" and 3/8" deep, then fill the cavity with a compound of 5 parts Potassium Clorate, I part sublimed (flour of)sulphur, 1 part ground up briquettes. Mixed in a slurry, then dried.
Anyway, sealed over with beeswax and very carefully loaded, 3 shots would cut off a 12" aspen(poplar).

After I found out (from a chemist) if mixed in a slurry, that formula became very sensitive to detonating for seemingly no reason, I quit using it. Apparently if not mixed in a slurry it is more stable. I quit it's use and did not test that.
Apparently the formula was made illegal in Great Britain in 1898 due to it's instability, however, for years that formula was used in pill locks and tube locks as simple percussion, resulting in compression would set it off.

Good stuff, maybe not.