After countless calls about our Canooter Valve being too tight (.223/5.56) we fed it some Wheaties and opened it up to .30 Cal. The Dirty Thirty is meant to swallow your larger caliber rounds. Hearing safe on a Bolt action 300WM hunting rifle so your 300Black Out will sound like a gaseous emission. Just like our original Canooter Valve the Dirty Thirty was designed to be compact robust and still keep the cost of owning a suppressor under $500 including the cost of a NFA stamp. - 4 Overall length - .30 Cal 5/8-24 threading - Other Calibers upon request - 1 5/8 Diameter - 13.9 Ounces - NO BLOWBACK through the charging handle - Made from 416 Stainless - No Barrel Restriction - Full Auto Rated - Custom Serial Numbers are available upon request