English Fowler flint 1-1/8" hooked breech plug, 7/8-14 thread - Track of the Wolf
Amazon.com : Thompson Center IMPACT Breech Plug for IMPACT Muzzleloader Rifles with Advanced Extraction, and Fouling Prevention for Black Powder Rifle Hunting, and Shooting Accessories : Gunsmithing Tools And Accessories : Sports
Wheellock pistol build 1650 pt. 4 making the breech plug - YouTube