The True Precision® Threaded Barrel for Gen 1-4 Glock® 17 is an easy-to-install, drop-in barrel upgrade for Gen 1-4 Glock 17 pistols. It features an advanced proprietary broach cut design for increased accuracy potential with broach cut 6 groove rifling that allows the use of all ammo types to be used safely, including cast lead. This precision barrel features a 9mm 1/10Rh twist and 1/2x28 threading for compatibility with muzzle devices such as suppressors and compensators. Constructed with 416R stainless steel. High heat integral O-ring lock thread protector included. Fully supported SAAMI spec chamber. Lifetime warranty. Made in USA.