Further note, Tom - the reason I added up ball size and patch thickness was to show how to show what patch to try with what ball and that the .010" patches you've tried are useless in trying to get a decent seal. A seal is needed to soften the fouling and to keep the powder gasses behind the ball.

A good patch is actuall suitable for many shots, not just one. If the patch is good enough, it will maintain it's integrity, "could" be re-lubed and used again, and again. I've done this to prove it works. I'm not suggesting anyone else try it, but no real reason not to. The accuracy should be unchanged.

Your load is .715" + .010" + .010" = .735".

If the bore of those guns is tighter than 12 bore (I haven't measured one) at .724" as some have suggested, then .724" + .008 + .008" = .740". With your groove diameter at .735", there is no seal and no compression in the bottom of the grooves. Blowby, burning, fouling buildup and poor accuracy is the result. POI cannot be trusted as the accuracy is variable due to the gas blowby.

If they are indeed, 12 bore in bore size as Pedersoli says, at .730", then .730"+ .008+.008= .746" - even worse in regards the thin patch. There is absolutely no seal, not even close and the combination cannot shoot well. If powder gasses can get past the patch, then the ballistics are all screwed up and the gun barely shoots better than a smoothbore, except with tiny charges creating huge trajectories and poor killing power. Of course, deer are easily killed, even with ML pistols, not so a moose or big bear at longer than pistol ranges.

As the powder charges go up, pressure also goes up and it takes a tighter load to seal. Some guys have good luck with wads between their patched ball and the powder while others do not. It is certianly worth a try as Supercracker suggested.

.010" are actually quite useless or next-best thing to it, as they are also too thin for cleaning patches. To clean well, they need to scrub the bottom of the grooves - hard.

For cleaning, I believe the jag should be sized to allow a VERY snug fit with 2 layers of flannelette cloth - old baby diapers works splendidly. I use new flannel material as it's been 30 years since there was a baby here that used flannel diapers.

I went through all the trials and tribulations of load development many years ago and know how you can feel at times - quite frustrated is how I felt. Bear with it and you'll find what is required for good shooting, accurate and clean shooting loads. You can have it all.

We've discovered that certain combinations work in ALL rifles - yes they are slightly different and need special attention to details - but that's usually the powder charge that needs attention. They all shoot the above combination very accurately.

When I look at the rifles on any weekly trail shoot at our club, I see mostly balls .005" under bore size (the odd fellow uses .010" under for hunting - same patch) and ticking or denim patching from .020" to .025" thick. None have any fouling buildup for an entire day's shooting, never have to wipe their bores during our shooting day and go through up to 80 shots that day.

What we've found is that all rifles respond to a ball .010" to .005" under bore size and a 10oz.(.022") denim patch.
The larger the bore, the smaller the ball in relation to the bore size and a thicker patch can be and maintain excellent accuracy. For example, your 12 bore will shoot well with a .690" or .700" ball, as long as the patch thickness + ball size is very much greater than the groove diameter. Thus with a .700" ball, you'd need .740" - .700" = .040" divided by 2 = .20" patch just to go to the bottom of the grooves. We know that .006" compression per side is about minimal for good shooting, so the patch should actually be .020+.006 = .026". That's the patch needed for the .700" ball. I'd think the railroad ticking (red/white/blue striping) would work, as it's .025" thick on my calipers. It's only .0225" on my mic. How you measure and what you measure with makes a difference too. The .690" ball would require a .030" patch - that's 12oz. denim on my calipers. That size a ball would require a bit tighter fit to seal the pressure behind it. The thinner patch might work, but unlikely with heavy loads. It depends on what you demand for accuracy.

In the smaller bores, the ball and patch must be tighter than in the larger bores - due entirely to the pressure generated. The higher the pressure, the tighter the combination must be. For a 12 bore to generate over 10,00PSI, would require more powder than you will want to shoot, while a .45's /rangeload will be over that pressure. This is why the smaller bores need/demand thighter combinations, but the larger bores also need to be snug. Their somewhat lesser demands do not allow sloppiness in load developement.

What remains is for the individual to use enough of the proper lube - it has to be wet/filled with lube whether that lube is melted into the cloth, or an oil like Neetsfoot oil is used, where the patch is simply wet with it. The thin patches cannot contain enough lube to soften the powder fouling left in shooting. Water based lubes are not useable for hunting as they will leave a rot ring in the bore where they sit. An oil or grease must be used. Neetsfoot oil has proven to work well for many shooters. That's pure Neetsfoot oil, not neetsfoot compound, which is a synthetic and does not work with bp fouling. During the winter, my brother used Neetsfoot oil only for lubing his rifle patches. He shoots mostly his J. Kuntz .40 rifle, with 68gr. 3F GOEX. That's a 2,200fps load, probalby running 15,000psi or a bit more and the 80th shot loads more easily than the first - yes - more easily - there is never any fouling buildup and he never has to wipe while shooting. Simple cold water cleanup works just fine.

In warm climates (ie:Texas), picking a lube is easy - even beeswax + Vaseline lubes can work, or Beeswax + Neetsfoot oil or mink oil will work, or Neetsfoot alone. I've never had as good results as in clean shooting nor as good accuracy with Olive Oil in bullet(BP Ctg.) or patch lubes.

Hope this gives more food for thought.