WB
Huey is right. It's probably ok at modest speeds.
Tuesday, September 03, 2019, 07:21

But don't pooch your lip if it happens. There is a huge difference in power pressure curves. It can push it suddenly very hard or progressively through the bore. The difference between say Bullseye and 2400. You "could" make it lead if you tried, with both. Or say a .357, make both work perfectly.

That alloy slug is being forced from a stop to very high speeds to slam through a "funnel" forcing cone or throat into spiral rifling. The rifling cut into the metal and it's malleability mandates how it handles the spiral forces. It can shear, or with roughness, smear to leave debris behind. Begin the journey too fast and it will shear being pushed faster than the alloy can adapt. Or if the alloy is too hard it can break rather than bend. A progressive push is better than a sudden kick.

I have my own witches brew recipe that I've found over the years that works for me. I have absolutely no idea as to the hardness number and frankly do not need another element to cloud my fun. Then of course I can add a gas check or powder coat to add resilience if I think it necessary for the application. I am experimenting with almost pure lead and powder coating now to get subsonic expansion with no leading. Old BP revolvers did it 150 yrs. ago with naked pure lead balls.