The Grey Ghost Precision® Match Grade Threaded Barrel for Gen 3-5 Glock® 17 Pistols features precision-machined 416R stainless steel with a corrosion-resistant black nitride finish. Machined to ultratight +/- 0.003" dimensions for consistent accuracy with a SAAMI-spec match chamber. Boasts a 1:10 twist rate and 1/2x28 TPI threads. Includes knurled thread protector. Compatible with Gen 3-5 Glock 17 pistols ONLY. Best used with brass-cased, factory-loaded ammunition.