Hey Sabotloader,
Didn't check the float with a dollar bill, but I used a sheet of printer paper that I cut similar to the width of a dollar. It slides, but there's some slight tension.
The time between shots was about 6 to 8 minutes, so I don't believe the heated barrel is the problem, your call. I may make some aluminum pillars to stabilize the barrel.
I'm use to extreme accuracy with my bench rest centerfire rifles. Guess I'm asking too much from a muzzleloader.

But I can shoot a consistent 2" group @ 100yds using ball & patch with a .50 cal Hawken I bought for a TV commercial I was shot for Hawken Smokeless tobacco.

I bought the rifle from a man, since dead, in Colorado. I've been trying to find out if the rifle was a reproduction or original. The only marking is S. Hawken St. Louis on the barrel. No brass only a pewter cap on the stock. A spring and nib broke in the lock, but so far no one, including Dixie, has been able to identify the lock.
I may post pixs of the Hawken on the site. Maybe someone can help.