What are thread pitch sizes for threaded barrels? Rachel Zorn September 18, 2017 16:09 Updated Follow 9mm/38 super: 1/2×28 .40/10mm: 9/16×24 .45: .578×28 Related articles What is the recoil spring weight in my gun? Why should I choose STI over other brands? What makes the Costa Carry Comp, DVC Open and DVC Steel barrel and compensator superior? Can I convert my gun to a different caliber? How do I take my STI firearm apart and reassemble? Comments 0 comments Please sign in to leave a comment.