Our Match-Grade Barrel for the GlockA(R) 20 fits ALL generations of G20 It's an excellent replacement for a shot-out factory barrel or for completing a pistol based on the G20 platform. And it's the ideal tube for a custom gun built on a Polymer80 frame with a Brownells Slide on top! Each Brownells Match-Grade Barrel for GlockA(R) 20 is machined from hardened 416R stainless steel to precise dimensions, so it's a drop-in fit on most guns. The tight lockup helps ensure superb accuracy, too. The extra-hard Black Nitride finish resists surface wear and stops in its tracks whatever corrosion might try to challenge the stainless steel. This 9mm Luger (9x19mm) chambered barrel Mfg: Brownells