It was not obtainable on thirty” barrels, deer guns, focus on guns or to be a retrofit. This patented system permits the shooter to work with a wrench to alter the shotgun to whole, modified or enhanced cylinder chokes. Remington also extra the twelve-ga. Design 870 SP Exclusive Intent Deer http://cesarpfvja.get-blogging.com/17140210/the-definitive-guide-to-remington-gauge-pump-action-shotgun