I really don't know what the deal is with my factory Glock and aftermarket 40 cal barrels and their hatred for lead boolits. I've tried light ones up to heavy ones (MBC 140 gr to 180 gr). I've tried a half dozen powders from fast to slow burners- all the most popular ones in various quantities (usually light to med loads). I've tried another brand of molly coated boolits as well. Nasty leading from all of them within 2 or 3 mags. I really wish I could crack the code as the price diff for 1000 lead vs. 1000 plated or jacketed in 40 cal might amount to some real money over time. I just broke down and ordered a buttload of x-treme plated. Maybe when I have more time & patience I'll try some custom sized lead, .402 or .403, instead of the standard .401. Maybe. Oh yeah, and the copper Chore Boy on a jag to clean the skid marks outta the barrels. Works ok but kinda slow IMHO. The lead remover "rags" sold by Casey and Kleen Bore and cut into patches and run in & out of the barrel on a rod really work fast. Unfortunately I've been getting pretty good at it.