Andy- lots of good info in this thread. The most important is that of the going to a thicker patch. If you are buying pre-cut patches and insist on using the .490" ball, then I suggest .020" patches - minimum - for good longer range accuracy and for clean shooting.
If the patch is too thin, hot gasses and flame blast by, fouling the bore and destroying accuracy. Even a smoothbore will shoot a 1" group at 25 yards. 50 yards is the minimum range to see what "the load" will do.
Too, a .50 will need in the relm of 65gr. 3F to 85gr. 2F powder to shoot well at 50 yards and beyond.
As to lube, most of us up here in the North, use a concoction of winter windshield antifreeze, with a few ounces of soap, neetsfoot oil or olive oil in it. Shake, pour over the patches to saturate them in a container - steel or plastic, then pour off the excess back into the container. The exact recipe means little, but I have achieved better longer range accuracy using LehighValley lube (not available any more) or Hoppe's 9 Plus BP lube and solvent. These slippery lubes actualy require more powder be used to achieve the same accuracy as less slippery lubes, like water or spit based.
Like Roger, I find few lubes that shoot better than plain spit. Easy to do with pre-cuts - less spit is needed. Merely licking the patch is similar to using no lube. The patch must be WET. The easiest way to do that is always have one in your mouth, so by the time you are ready to use it, it's saturated. While loading, put another dry pre-cut into your mouth so it's wet when needed.
Dry patches might work if you like wiping the bore every shot or every 2 shots. The problem with that, is the an ever-changing bore condition, which doesn't happen when using well-wet, tight combinations. Using a tight combination with wet patches, ensures never having to wipe the bore from the start of shooting to the end, and the bore never gets 'fouled' - it's cleaned when you load the next one and stays consistant for every shot.
A well shaped muzzle's crown is vital to allowing easy loading of a tight combination. If the ball is hard to start, the muzzle's crown is too sharp. This is a hard and fast rule, not an opinion. We've proven this time and time again over 40 years of shooting. The smoother the crown, the easier the ball and patch swage together into the rifling for a tight fit.
