I have a Remington 870. Back at tax time, I got a 20" barrel for it since it was to become my bedside gun. The barrel came with a tactical choke. I love the barrel length but the tactical choke adds 2" to the barrel length. I know not to fire a shotgun with no choke in it since it'll mess up the threads but, I need to know if someone makes a choke, like a cylinder choke so I can still shoot slugs, that doesn't add any, or very little, to the overall barrel length?