Try the alloy you have, good chance it will work just fine. There's nothing magical about hard bullets. Leading is a symptom of poor fit or high pressure. It may be difficult to avoid high pressures with a .40 but it's worth a try.
Life Member NRA, TSRA
Smokeless powder is a passing fad! -Steve Garbe
I hate rude behavior in a man. I won't tolerate it. -Woodrow F. Call Lonesome Dove
My favorite recipes start out with a handful of used wheelweights.