On your hold of the barrels -- I typically hold further forward, with full wrap around the tubes, standing or sitting or kneeling. I really manhandle them, with just enough gap between my thumb and forefinger tip to see the sights. I keep considerable pressure back into my shoulder and a good cheek press into the stock, eyes low and wide open.

Getting better for you this time?

On the unburnt powder, how tight is the wadding?
How tight is the neck to bullet fit?

Cheers
Tinker