TexasCHLforum.com

The only "issue" I'm aware of in regard to loading for Glocks is that lead bullets and the polygonal rifling don't get along very well - the lead can build up to the point that it starts raising pressures more than is acceptable.

Some folks claim there's no issue here, and that they've personally fired a gazillion cast bullets through their Glock.

Maybe they have, but I would stick to jacketed or plated.