Constriction -us vs. eu - Browning Clay Burner Extended Choke Tube

I've been shooting sporting clays for a long time on the 725 (now 825) platform along with owning Kolars, DT-11s, etc. THE MAIN POINT OF THIS REVIEW IS THAT THESE CHOKES ARE SUPPOSED TO REPRESENT CONSTRICTION BASED ON DIFFERENCE FROM BORE DIAMETER AS OPPOSED TO WHAT COMES WITH YOUR GUN IN AMERICA. HOWEVER THESE CHOKES ARE DESIGNED AND DELIVERED WITH EURO GUNS. IF YOU ARE SHOOTING AN AMERICAN CITORI (MIROKU) YOUR BORE IS WIDER, ABOUT .005". SO IF YOU WANT YOUR CONSTRICTION TO BE AN EXACT NUMBER go one constriction up, ie. buy a 25 if you wand a mod. But a 15 if you want an IC. Other than the constriction confusion, I will say the DS is one of the best, if not the best chokes I have used. Entirely due to the DS system. The closest thing I've shot to this is the new DLC chokes from Beretta as far as being clean and never having problems. Everyone who shoots a lot knows that chokes are chokes, for the most part. Aside from parallel sections and fancy coating materials, find a choke that patterns well for you and shoot it. I will say that these chokes are somewhat jugged which means they pattern a little tighter than their actual constriction. thus the naming system for the OG chokes. I've found that 15-20 (true constriction of .0105-.155) will break anything within reasonable shotgun ballistics. That being said the factory IMOD (.0125) is almost identical in constriction to a Muller 2 but will stay tighter longer if you throw a slow 7.5 out of it. The factory MOD (.008) or Clay Burner 15 (.010) is a great choke for anything a beginner to intermediate shooter would need.