is use lead reloads in glocks. for 9mm, the least leading i noticed is when i used slower burning powder and at lower velocities. around 1000 to 1100 fps using 124gr. lead heads. any faster than that leads to rapid lead build-up. and shorter case life. case resizing is also a must, glocks being military pistols have a looser chamber than them match grade stuff. remember to scrub the lead out every 100 rounds
for .45 caliber glocks, i have problems using local brass. the chamber is so unsupported that the brass bulges near the case head. have to find those rpa cases, they are the strongest cases that i have tried so far.
anyways, an aftermarket barrel will lengthen case life and lessen the lead scrubbing
hope this helps