To clarify....
NCOWS Rules and Regulations
No matt-finished or brushed-finish stainless steel firearms are allowed except as specifically exempted in these Rules and Regulations, e.g. only those stainless steel firearms whose finish resembles an original nickel-plated finish.
No modern commemorative firearms shall be allowed
Projectiles shall be cast lead or lead alloy. No metal-jacketed projectiles shall be permitted. Muzzleloaders shall use round ball or elongated projectiles if such were original to the firearm.
Muzzleloading percussion firearms shall be original to the period or authentic reproductions.
Cartridge firearms shall be original to the period or authentic reproductions of original makes and models. “Short-stroke” modifications to lever-action firearms are not allowed.
Sights for all firearms shall be of original design or configuration.
Approved calibers and loads include any that were introduced prior to or during the period of 1865-1899 and that were originally introduced as a black powder load. Common examples include but are not limited to: .22 rimfire, .32-20 WCF, .32 S&W Short, .32 S&W Long, .38-40 WCF, .44-40 WCF, .44 S&W American, .44 S&W Russian, .45 Long Colt, .45 S&W, .45-70 Government. Any cartridge designation that was not originally introduced as a black powder load will not be allowed except for appropriate firearms in the smokeless cartridge division only, or for specifically-designated shooting events. .38 Special/.357 Magnum and .44 Special/.44 Magnum cartridges will be allowed if loaded with black powder or with smokeless powder to black powder velocities.
.22 caliber hand guns for main stages are to be pocket pistol/derringers only. .22 revolvers and rifles are restricted in use for specialty shoots only.
Single-Shot cartridge rifles shall weigh no more than twenty (20) pounds for official NCOWS competition.