When you "slug" a barrel, that means you take a soft lead slug and drive it from the muzzle and out the breach. Then you take a micrometer and measure what the actual barrel size *really* is -- this can vary somewhat from rifle to rifle. Jacketed bullets aren't affected much by it but I'm a bullet caster too.
If you've ever heard anyone say "oh man you can't shoot pure lead bullets in those things, they lead the barrel!" that's telling you at one time he tried some cast bullets that weren't sized properly for the barrel. Typically you need to size your cast bullets .001-.002 OVER the size of the barrel in order to avoid the leading issue. Ranch Dog here is a mold maker although I think he's closed up shop and may have retired from making custom molds, he is an authority on cast bullets and proper sizing.
By using this method, I've shot thousands of my own cast bullets -- made mostly from recycled automotive wheel weights, and never once had a leading issue. Some of them out of my big guns 45-70, 444 Marlin, etc are moving out pretty quick and still no issues.
If you're not a reloader, you may need to try different brands of 158 grain before you find one your rifle likes. Since I load, I can load them to fit my particular rifle. Hope that clears up some of the mystery for you, I've been reloading for 30+ years and casting for 20 although the casting part I've only been sucessful with for the last six or seven year --- if you ever get into this feel FREE to ask me questions. Ranch Dog can be a big help also, how the hell he makes those tumble lube bullets work is amazing...........
Art
RickinVA wrote:Beautiful rifle! I recently purchased the .357 carbine, but think I will need a rifle now too. Thanks for your commments on twist and bullet stabilization. I've been planning to use 158 or 180 grain ammo for deer and didn't know this could be an issue. I don't reload. What is "slugging" the barrel?