Actually, in a recent thread on another forum with contributions by one of the most experienced and trusted shooters I know, it turns how he and a number of other folks have shot a lot of cast bullets with no lube at all and still got no leading. That surprised me, as I'd simply never tried it, having been suckered in by conventional wisdom to always using lubes or paper patching. It is a question of sizing and alloy selection and gun condition being coordinated such that no bullet scraping or gas cutting is involved inside the bore or chamber. And, on reflection, why not? Lead alloys are typically more slippery against steel than gilding metal is. That's why babbitt alloys alloys can be used successfully in bearing journals. But rough or constriction plagued bores, undersized chamber throats, undersized bullets, and unnecessary bullet jump to the lands can all contribute to leading.
A smooth bore surface in a 1911 barrel doesn't lead much if you load to headspace on the bullet. I've run over 3000 rounds without cleaning in my school gun with no appreciable lead accumulation. Light lead traces form just beyond the throat almost immediately, then just stop growing. They seem to be shooting themselves clear as fast as they accumulate thereafter.
Years ago I put a front sight extension on a bull barrel Ruger pistol of mine that overhangs the muzzle. It's remarkable how thickly the lead splatter builds up on it's underside. It's true that .22 bullet lead is soft, but so is the muzzle blast shaving it off pretty mild as muzzle blast goes.
So, what causes lead contamination at ranges? It's both primers and exposed bullet bases. The primers create the water soluble lead compound smoke that is the immediate airborne health hazard. But lead dust all over the range is from gas cutting of bullet bases by both muzzle blast and revolver barrel/cylinder gap blast. Pure lead metal itself isn't particularly hazardous, but the fine dust gradually oxidizes and contaminates the ground and can be picked up on shoes and hands and even be blown around with other dust to some degree (though it's heavy). So it's a factor, though I tend to think it's more an EPA fine hazard than a health hazard. The health risk from the lead dust is essentially nil if you wash your hands before eating after you shoot. I base that assessment on lack of remarkable blood lead levels in myself and other range rats I know who've been tested. It seems like you'd have to work at it to get that stuff in your system in quantity.
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Last edited by Unclenick; September 11, 2012 at 01:57 PM.
Reason: typo fix