In 45 ACP, both .452" and .454; shot very well in the Glock 21's OEM barrel. Alloy was 92/6/2, lube was Javelina 50/50, all boolit designs had conventional lube grooves. These boolits were Lymans #452374 and #452460, Lees 230 TC and 200 SWC. All boolits went into the hundreds with round count; there was no discernible leading present.
My theory--such as it is--the 45 ACP is a generally lead-friendly caliber anyway. 9mm--40 S&W--and 10mm are more hostile environments for cast bullets, being more akin to rifle conditions (high pressures, fast twists) than to handgun conditions. To date, I have "chickened out" from using lead boolits in Glock 9mm and 40 S&W barrels, and have opted for aftermarket barrels featuring conventional (and slower twist) rifling forms and fully-supported chamber designs. This is NOT a recommendation or advice--it is just my mode of operation that flows from an abundance of caution and laziness. I don't want to re-shoot and re-test my daughters' 9mm and 40 S&W Glocks as extensively as I did the G-21.