Haywire,
BP loads and BP substitute loads should be used with cast or swaged bullets only. Must also be lubed with a lube thats designed for softening the fouling left behind from the powders. (Black, American Pioneer, 777)Doesn't matter, they all leave fouling to some degree. The lube should soften it enough for the next bullet to clear some of it out.
Many homebrews out there for bullet lube that all work great. One of my favorites is beeswax, murphy's oil soap and a little crisco all whipped together.