Ballistic Products .678 375 grain Foster Slugs are a near duplicate of a Nessler Balle. I'm not sure what the "Oz" equivalent of 375 grains is.
Tracing paper cartridge, lubed with Wonder Lube 1000. 60 grains of Old Eynsford 2f.
Loaded like a Pritchett, they glided down the bore until the top half of the bore got "crusty" . Maybe Swiss 3f next time?
At about 40 yards , I fired 5 in the paper then decided, the paper was kinda shredding in the fouling......I loaded 2 with no paper over 60 gr of 2f, with a smear of lube on the bullet. Accuracy was identical with no paper, in fact those two shots fell right into the existing cluster of 5 from the wrapped slugs.
I have a rear sight on my .69 1816 Springfield that is roughly at a 150 yard "zero" so I was playing with half sighting , quarter sighting , etc. If I had just picked one and went with it this group would be tighter. In fact I was going to , but ran out of time as I had to do other things today. I'm thinking these will group at 50 and might even hold up for hits on man sized paper targets to 100, and maybe even decent hits at 200.
Some were knocked out of round in shipping but nothing a push through the .680 sizer won't fix.
Some may say "I can do the same with roundballs" but bear in mind, originally the Nessler Balle was a bit less accurate than Round ball but after 100 yards or so, the Nessler retains accuracy while the round ball sharply declines. I'll have to get these out to longer ranges. I'm thinking that the paper may be an unnecessary thing and maybe hindering the loading process. Historically these were kept in paper but at .678 - .680 they were probably made for a .70 or .71 bore French or Austrian musket . I feel a hot dip in SPG lube and a push through my .690 sizer will put a nice layer of hard lube on the slug and I can use them like a Minie.
Or, give running them through a .670 sizer a shot , and use the paper. My goal is to find a slug that works and start casting them myself at some point.
Results with the Fury Custom Bullets .680 slug were less encouraging but I only fired 2 of them...the first one , wrapped in paper, sounded like a blank and hit way off point of aim, the second one a loaded bare and it tumbled into the target . I guess they just don't stabilize , the center of gravity is off......or he uses an alloy and they don't obturate. He says they're pure lead though but maybe different people's opinions of "pure lead" is different.