Have you considered paper patching?  It was still state-of-the-art when our Krags were made. No gas checks, sizing, groove or pan lubing. Just get a mould that throws .308 plain base bullets at your desired hardness ( and with paper jackets, wheel weight alloy is as hard as you need up to @ 2400 fps) and patch out to .312 - .315. Finger lube the patch with a Vaseline / Beeswax mix (also waterproofs). It's fully in keeping your black powder and beef tallow experience.  :)

Just a thought.