Back when I had my CCW class, I used my SA Ultra Compact in .45, which has been discontinued for years, the class supplied the ammo blazer brass, my gun would not feed it, no matter what, I tried other brands to see if it was the gun, Remington, Winchester white box, federal, all fed but the blazer still wouldn’t, milked the case rim and it was somewhat thicker and I’m thinking it wouldn’t slide under the extractor at times, now just for fun I tried there blazer aluminum case, worked fine….some guns are just finicky on ammo, now I tried the blazer brass in my colts with no problems…..just the way it is