Many moons ago, Glock issued a warning about shooting lead bullets through their pistols. The reason for this warning was the failure of several barrels after shooting them. The Glock line of pistols use a polygonal rifling design. This design is different in the lands, and grooves look more like rolling hills and valleys as opposed to bluffs and valleys. Because of this warning a myth has been propagated; shooting lead bullets will cause fouling in a polygonal barrel. This isnt really the case. http://www.gunnews.com/myth-polygonal-barrels/ I know from my use of cast bullets over the years in the factory barrels of 9 mm,40 S&W and 45 acp,for 95% of my shooting I would agree. Each shooter should make up his or her mind,I know for myself I long ago made mine and I have no regrets. SJ 40 Wanna kill these ads? We can help!