I finally located the Chore Boy copper pot scrubbers yesterday, after getting blindsided by the copper-plated knockoffs--fortunately, no scratches. Tried 'em last night, after shooting 250 rounds of fairly warm lead reloads--worked good, but not perfectly--so Brian must have it about right.
I've shot three different lead bullet brands through my j-frames recently---and I've tested all of them for hardness.
1. Penn Bullets are BHN 21. They take less powder to reach obviously higher velocities.
2. Mastercastbullets.com are BHN 15-16 for non-custom orders.
3. The latest LGS brand from a local lead caster is RedRiverBullets.com (no such site exists)--BHN 10-11.
4. And, I've shot the Hornady and Speer swaged 158LSWCs-HPs; currently load the Speers for my "FBI Load" testing.
Most of the powders used are in the 25-35 range on the Hodgdon burn rate chart--e.g., WSF, #5, SR-4756, etc.
I find the lower or midrange BHN bullet leads the least when it is sized properly--in my 640, the Speer swaged HPs leaded least. So far, all the guns need .358 bullets in the softer numbers, and Penn .357s deliver lower EDs / SDs. The Speer swaged,I believe is .3565--so obduration based on powder burn rate and charge weight, etc., probably plays a part.
FWIW.
Jim H.