I've found that finger tightening the Optima chokes on my 391 sometimes isn't enough and the tubes will back out of the barrel. The little wrench supplied by Beretta is meant to snug the tubes in just a touch but it's not a very convenient system. I find the Carlson wrench combined with some Briley grease on the threads seats them in tighter, keeps them in place and makes if a lot easier to remove the chokes when they need changing.