I shoot lead in my .40 Glock.
But the bullets need to be very hard to engage the polygon rifling.
All due respect, I disagree.
I've been told that semi-autos don't like lead bullets, especially Glocks
Also disagree.
Please, no disrespect is meant here.
The truth is that Glocks like lead bullets just fine, as long as they fill the bore.
Semi-autos like lead bullets just fine.
What doesn't always like lead bullets, particularly soft lead bullets, are sized 9mm and 40 cases.
Unless my Glocks are special, I can say that Glocks in 9mm and 40SW will shoot straight WW alloy (much softer than MBC) bullets just fine. Air cooled. No hardening nonsense. But only if the cases are prepped correctly. And there's no off-the-shelf solution for 40SW. So hard lead might be the way to go. (My custom made 40 expander = instant accuracy and no fouling in my Glock 40!)
For 9mm, if you get an NOE 356/360 expander, you can shoot any cast bullet you want. In your Glock. They will shoot clean with either no or very little fouling. I have shot about two thousand cast bullets through a 9mm Glock without cleaning it... because it didn't need it. No chore boys. No shooting jacketed bullets to clean out the fouling. Just 2 thousand cast bullets and a clean bore.
Load some bullets and pull them. Measure the base with calipers. If you measure < 356, you will have trouble in your Glock bore. Fouling. Lots and lots of it. And tumbling bullets that can't hit a 10 foot circle at 50 yards.
I have measured pulled bullets squished by 3 mils at the base. These bullets fouled the Glock bore (9mm and 40) horribly. Couldn't keep them on target. But they weren't half bad out of a button rifled barrel. Changing nothing else but the expanders made the same bullets shoot as accurately and cleanly as jacketed out of anything.
This can indirectly be called a lead hardness problem, but it's misleading. Yes, there will be a cause and effect due to lead hardness. But that doesn't make it the root cause of the problem. If you fix your cases, you fix the problem. It's very simple. It's so strange that this is not common knowledge, yet. You have to hunt for the info and experiment for yourself to this day. When the answer is so simple. For some reason, black magic takes center stage among "gun folk." Seems like we would rather paint our bullets or play with alloys than to fix the problem once and for good. And shoot cheap bullets accurately and cleanly forever after.