I've shot glocks for over ten years. I competed at my club in action pistol and tactical pistol league. Glocks dont need aftermarket barrels, they shoot fine right out of the box. I shot against fellas with ed brown custom 1911s, STIs, Kimbers, and Wilson Combats, I'm not a great shooter but managed to place a few times. I shot factory rounds and didn't have any malfunctions until I started buying reloaded ammo from a local. Solved the issue by reloading my own on a Dillon 550 progressive. Id take the barrel out of the gun and drop every loaded round into the chamber to ensure function before matches. If it didnt drop all the way in it got put through a lee factory crimp die which full sizes a Loaded Round with a carbide bushing. I initiallly bought a stormlake barrel for shooting lead bullets. It has a tighter chamber than the glock barrel and gave me chambering issues but turning down the dillon crimp die or running through the lee factory crimp die stopped the problem it wasnt any more accurate than the factory glock barrel though.The cut rifling on the stormlake allows the lead bullets in a glock. And the barrel is shiny stainless steel..I carry a model 27 daily, nice compact with 11 rounds, same accurate reliable gun I shoot at matches. I have a 35 but hardly ever use it. Practice taught me effectiveness of the small gun out to 20 yds. More distance than that might not be considered defense. And there are better weapons for that.