Easily one of the most iconic pistol calibers in the world with more than a century of faithful use .45 ACP has been a go-to choice for shooters looking for a proven heavy-hitting round. Not only does the MkG RESOLUTE come chambered in this renowned caliber but it also makes use of commonly found and trusted Glock-pattern .45 ACP magazines and spurred the invention of our legendary Radial Delayed Blowback operating system years ago. - When full-size rifles are too cumbersome and pistols/SBRs don