Hello, While most all of the match rifles used a false muzzle to start Paper-patched bullets straight into bore..There are two distinct types of paper patches..the earliest used strips of paper..calculated to form up around slug as it was pushed into bore..just touching each others edge & not overlapping. On these, the false muzzles were milled with corresponding slots for paper strips to lie in.
The other paper-patch bullet--and the type I am thinking of is the wrapped patch..the same as the early breech-loaders used.
Now I know dyl doesn't have a false muzzle on his rifle..but I do know a bore sized soft-lead slug will obturate from the kick of real black powder to fill rifling grooves. Suppose he sized a soft lead slug to just under bore dia., & patched it up so as to be a snug fit in bore..I'll bet it would work..and he could get all the velocity possible with no leading.