I have read and been told Swiss BP cannot be compressed in a ML, yet I have also heard Swiss works great compressed in a cartridge.

[drpatton]

"Compression" is a rather vague term. To some people 1/32 of an inch is compressed. To others 1/4 inch is compressed. The internet gurus will say you MUST compress [fill in the blank]. Others say you MUST NOT compress [fill in the blank]. My B.P. ctg. rifles have the bullet seated from just touching the powder column to compressing the powder the depth of a grease groove or driving band depending on the rifle. All but one of my B.P. ctg. rifles use Swiss powder. My muzzleloaders have the bullet seated on the powder with the same amount of force each time. The amount of force is up to you. Just be consistant and don't crush the powder by slamming the ramrod down on the seated bullet. X

This makes sense. I have watched videos of guys topping off a 45-70 case with BP and seating the bullet on top of it. The size of a 350 gr or 405 gr bullet indicates a good bit of compression.