Backl in the Early Neolithic, when I was on a military pistol team, we were using up steel case 45 made for WW II, headstamped EC and ECS 42 and 43. We found that a drop of oil on the top round in the magazine extended the life of the 45 extractor, which was 1500-2500 rounds with steel case ammo. We were firing a lot of steel case and came up against that round limit fairly quickly.