Black Bore Blues

[denton]

I have a rifle that I'm doing barrel break-in on. It's quite a nice rifle, with a Pac-Nor barrel on an FN action.

The loads I have been using were made with a really, really old batch of H4831. It probably dates back to the days when Hodgdon was selling milsurp powder in paper bags.

Anyway, I shot 10 rounds, cleaning after each. Then I shot 30 rounds, cleaning after each 10.

Then, I noticed that the barrel is absolutely as black as the ace of spades. Evidently, that is from very high levels of graphite in that very old powder.

I've used JB paste several times, and a bronze brush dipped in Witch's Brew (solvent and mild abrasive). My right arm aches from swabbing that bore. I've got it down to the point that a patch comes out gray, instead of jet black, when swabbing after a brushing.

Anybody got any secrets for removing graphite?