Bear,
Thanks for the response. Let me see if I can help. One thing I forgot that was mentioned by Vanilla is throat to bore size differences. If the throats are smaller than the bore, you got troubles no matter what you do with the bullets. I doubt that is the problem but, hey, it's possible.

If those bullets are 11BHN and are .001" to .003" bigger than your throats/bore you should be able to get a load that doesn't lead.

As far as bevel based bullets go, I drive them in a Marlin 1894CB in 357Mag in excess of 1800fps with virtually no leading, some flakes after 50 rounds but easily cleaned with a standard brush and wet patches.

The powders you have should give good results with cast bullets.

Here is a picture of what Keith said about Sixgun Loads:

Now you will notice that he doesn't say too much about a Bullseye load for the 44Mag, special yes, and there may be more information available elsewhere to that regard, I'm not sure.

Try this though, if you will. Check the size of the bullets. Do they fall through the cylinder throats? Is all of the copper fouling out of the bore? Even though it is not seen, it can reek havoc with lead bullets. If you are sure that it is all out, let me give you a suggestion. Take the maximum load of Bullseye for that bullet and caliber and run about 50 round of it down that firearm.

If the bullets are big/soft enough, the Bullseye load will generated the highest pressure in the shortest amount of time which should cause the bullet to obturate and seal off the gases.

Have you ever heard of Lee Liquid Alox? There have been folks that coat their "store bought" bullets in it to keep leading from happening when shooting "gallery" loads. You may want to do the same.

Hope this helps. Keep us posted.