Once a charge of powder has been established, have any of you found that changing patch thickness is needed?
How are you lubricating said patch? ( gotta know that before I can answer)
I have found that with each patch there is indeed a variation of the powder charge. It might be only 5 grains (or less) that will dial in the sweet group.
Once I find the best charge for the patch/lube combo I'm using, I usually go back and vary the amount of lube I use for the patch. If I change patch thickness, it's like starting all over again.
You need to experiment. It requires shooting, it's the only way too find out.
The real key is to change only one variable at a time, Change the powder charge, or change the Patch, or change the Lube.
Most of my guns have a prefered "range" of powder charge with the ball sive I'm using. Say somewhere between 70-80 grns gives me the best groupings with a range of patching thickness, so I can limit powder range testing choices to 3- 5 shot groups useing 70-75-and 80 grns for that patch. then change patch and try again 70-75-and 80, etc,,,
Once powder charge and patch thickness has been established for best grouping, I go back and vary the lube amounts,,, but by this time with just 3 different patch thickness (all lubed the same) I'm 45 shots into the day.
It's easy to burn up a pound of powder and a few range sessions too find the best Ball/Patch/Lube for each gun. Some guns like .490 or .530 ball, others like .495 or .535 ball.
Hint; Most of my guns like a tight fitting dryish patch. This requires a Short starter yet still capable of using the rod and a few strokes to seat the ball.