The burn marks and the holes, are from the powder flame blasting past the ball and patch, in the grooves,
all one of them.
The guys are correct, thicker patch, or larger ball will improve patch integrity. Oft times it is much easier and
better to use a thicker patch with the same ball (especially in the larger bores. A thicker patch holds more lube
as well.
Rich is spot-on with his description of load differences seen on patches. With my old (1986) .69, the thin .022"
patches work fine up to about 90 or 100gr., but over that powder charge, the patches show burns. I need to increase
the patch from 10oz. denim to 12ounce denim to maintain accuracy and patch integrity.