bladesmith said:
I'm getting punk loads because I think of three things: bigger case volume, fiber wads, and a glued in overshot card [ no crimp means less resistance ] .
None of the above should be of any consequence in black powder loads. Think muzzle loader, none make any difference, and the over shot card is not even "glued in". Resistance, (built into the shell), is not needed for black powder, other than enough "pay load", weight of shot.
Brass cases are a PIA! What you are experiencing is blow-by around the wad column, and back around the brass case mouth. You need larger diameter wads, (especially the nitro card), and/or more, thicker or softer, wad columns. The softer or thicker material will allow the wad to swell out to the chamber walls, for a better seal. You are using a nitro card, under all this, right?
In my modern, chrome plated muzzle loader barrels, I use only the nitro card. A tight fitting one. (In some instances where I did not have tight enough fitting wads, I will cut them in half or more sections and load them separately, just to insure that they will "squash" out and give a better seal.) In some of the old antiques, one can not get away with such, since the "chamber" area is burned or corroded to a larger diameter, and one must then use fiber wads to get the wad column built up above the damaged area.
The troubles with brass cases are that once you get them swelled up enough to "seal" in the chamber, you are only a shot or two away from having to resize them and starting over again. They also "work harden" at that point, and will be even worse the next go around. (And I don't want to keep on shooting hulls swelled up enough that they need to be "levered" into the gun chamber! Not good for a cherished gun, to put the hinge through that wear and tear!) Plus one has to clean brass hulls, immediately after shooting, just like the gun, or you will have a corrosion problem.
I find the paper hulls a much better deal, but the Federal papers do leak, hot, corrosive gases back through the primers and into the guns action through the firing pin holes. Some one on here has said that they had good luck, sealing them with finger nail polish. I have not loaded any since to try that "fix" out.
I prefer Mikes Wads, over the old Circle Fly ones, but have not used any CFs since maybe a couple of owners, back. They might have improved them since I last bought any.
I do occasionally use plastic shot cups, (I have some cases of old Federals, shot cup only, designed to be used over card/fiber wads), with out too much problem in BP loads. (They are not legal in competition shooting), but do tighten patterns up, for hunting.
As to the residue, BP or plastic, left in the bores, use a spray of moose milk about every 5 or so shots. That will allow one to shoot all day, and never clean until you are done shooting. (Moose milk: Water soluble oil, water and a dash of dish soap. Use windshield washer fluid instead of water in the winter time.) Just spray down the open breech and let it run out the muzzles. Virtually all the crap will exit the muzzle with the next shot. Even works with plastic hulls, used with fiber wad columns. Just don't reload those plastic hulls the second time. Toss 'em.
Yes, BobK, components can be found much cheaper than Ballistic Products!
Clyde