Anyone have a 20 ga factory choke and decent caliper to measure the constriction? I asked the factory and they said it is a .575, but my caliper only goes 2 decimals and shows .56. I would expect it to read .57 if what thd Stoeger rep told me was correct, and I'm thinking it is a .565 or .562. I'm looking to get a better brand choke in the same constriction since the factory choke gives a better 40 yd pattern than the Carlson .555. Thanks in advance!