Easy to install drop-in design; Advanced proprietary broach cut design specifically engineered for increased accuracy potential; Broach cut 6 groove rifling allows for all ammo types to be used safely, including cast lead; 9mm 1:10" RH twist rifling; 1/2x28 threads with included thread protector on threaded versions; Threaded versions include Viton high heat integral O-ring lock thread protector; SAAMI spec chamber; Improved overall fit from OEM with added chamfers, improved radius cuts, and other additions for a better than OEM barrel; Improved feedramp design over OEM for more reliable feeding of defensive ammo; 100% Designed and manufactured in the USA with USA sourced certified 416R stainless steel