scope, the scope may be offset. Any sighting device programmed to activate the firing mechanism is prohibited. Stocks can be hunting style; thumbhole-type stocks are not permitted. Trigger pull can not be less than . Rifles must be equipped with a functional safety, and all safety features must be functional. A hunting style contoured barrel that tapers from chamber to muzzle must be used, while bull barrels are not permitted. Factory tuners that do not act as a muzzle brake or compensator is permitted. Maximum barrel length is , including tuner. Magazines may not be loaded with more than five rounds. Anschutz is the manufacturer which totally dominates the smallbore silhouette rifle field. At the 2007 NRA Smallbore Rifle Silhouette National Championship 71% of all of the standard rifles were Anschutz rifles, 67% of the hunter rifles were Anschutz rifles. IMSSU Silhouette Rifle Small Bore Also called smallbore silhouette rifle. Identical to the description of the high power silhouette rifle, except that the rifles are chambered for only factory loaded .22 caliber (5.6 mm) short, long or long rifle rimfire cartridges. Hyper velocity rounds are not allowed. IMSSU Hunting Rifle Small Bore Also called smallbore hunting silhouette rifle. Identical to the description of the high power hunting silhouette rifle, except that the rifle may be a single-loading rifle, the weight may not exceed , the rifles are chambered for only factory loaded .22 caliber (5.6 mm) short, long or long rifle rimfire cartridges, and barrel tuners or additional weights are not permitted. U.S National divisions Competitions in the United States are held by the United States Metallic Silhouette Association (USMSA), which follow NRA rules in the U.S. and IMSSU rules in World Championships. NRA Cowboy lever action silhouette Any lever action center fire rifle .25 caliber (6.4 mm) or larger with a tubular magazine of original manufacturer or replica thereof. Only rimmed cases loaded with round or flat nosed bullets are used. Exception: .30 Remington and .35 Remington are allowed. NRA Smallbore cowboy rifle silhouette Any lever action, pump, or semi-auto rimfire rifle with a tubular magazine. Only .22 long rifle ammunition is allowed. Hyper velocity ammunition is prohibited. NRA Pistol cartridge cowboy lever action silhouette Any lever action rifle with a tubular magazine. Only rimmed pistol cartridges loaded with round or flat nosed bullets are used, i.e. .25-20 Winchester, .32-20 Winchester, .38 Special, .357 Magnum, .38-40 Winchester, .44 Special,