Just a general statement about shooting patched round balls...Guys, you have got to check your patches...I put a tarp about 15 steps in front of the muzzle...It's not just burn through that affects accuracy, its also patches tearing when loading or on sharp lands when coming out of the barrel...So even if you are using an over the powder wad, if the patch is being cut or torn it will affect the accuracy....It might even group "decent" with torn patches, it just depends on how much it is torn...

I have a custom .54 with a Ed Rayle barrel, deep cut rifling at 1-72 inches...I can shoot store bought .018 and .020 patches and they are torn after the shot...I can drop back to .015 patches and I get burn through....But, I can go to WalMart and buy .018 pillow ticking, wash it a couple of times, throw it in the dryer and lube...Bingo, the gun groups better than I can shoot....

Now, the gun will shoot 2 inch groups with an occasional flyer with the store bought patches, but the difference in washing the bulk was well worth the switch...I went through a time that I tried all the wads, etc...I'm now convinced that picking the correct patching and lubing properly is probably the most important part of the equation...