The second was 50 rounds or so of a buddy's 200gr SWC .... Oregon Trail cast bullets ..... my notes say they averaged 892 f/sec out of his gun, which does not sound "hot" for a 200gr .45ACP ..... they were sized .452, same as my plated bullets are......
In both cases, the bore was a PITA to clean.
It doesn't matter what size the bullets were, if you don't know what size the barrel is. It is not uncommon to see .45 Auto barrels around .454".
If plated stuff is working for you; then stick with it.
I'm simply trying to point out that leading issues are nearly always a byproduct of an improperly-fitted bullet; and/or people trying to shoot alloys that are too hard, because they think it will make up for not measuring their barrel.
Occasionally, you'll find instances where you can blame the barrel itself. One example is my POS Taurus PT-138 .380 Auto. At the chamber and at the muzzle, it measures .358"x.359" in the grooves. To properly seal that bore, I would need a bullet that is at least .3595" in diameter, but .360" would be even better. (The difficulty in locating a .380 bullet sized to .360" is a post unto itself.) But... it also has a loose spot in the middle of the barrel. I don't know how big it is, but I do know that a .359" slug will not touch the bottom of the grooves, and light can be seen around it.
That loose spot is enough to cause significant leading. However, situations like that are quite rare. My current loads don't lead at all, though. To maintain a gas seal in the barrel, and prevent leading, I got my hands on some hollow base lead and hollow base plated bullets. As the bullet travels down the bore, the skirt maintains a proper gas seal, and I get no
leading. ...and that's from a bore that's closer to 9mm Makarov, than .380 Auto dimensions, and has a loose spot in the middle.