After testing Beretta original mobile chokes versus Briley extended, there were no differences except for the ease of removal. They were the same constriction as the Beretta chokes. The aftermarket choke business is a bit of voodoo and a slight bit of trickery to get those denser patterns. They cheat somewhat by have slightly tighter constriction compared to the factory chokes. So, they throw a slightly tighter pattern than what they say the constriction is. Muller solved this by calling his chokes numerically. This way he cannot be accused of cheating. I have tested the Optima chokes and the Optima HP chokes versus the aftermarket. Beretta sent me a pair of LM flush Optima HP and they patterned slightly denser than the Muller 2. BTW, I have 2 used and 2 new Muller Optima HP 2 for sale! Beware of the heavy S/S chokes. They ad substantial weight to the nose of the shotgun and affect the "moment of inertia" or the liveliness of the shotgun. The ported one look ugly, are noisy and a pain to clean. Make sure that you have a guaranteed return policy if not satisfied!
Henry