WTB: Carlsons .575 for 20ga Rem. 870

[twyatt]

Like title says, looking for Carlson's .575 for remington 20ga 870. 
Will buy, or have a TruGlo Gobble Stopper Xtreme (.565) for trade in like new condition.  Choke was shot through 3 times and held an awesome pattern, but a touch tight for me with no optics on my gun.  Fiber optics were never taken out of the package.