Buy a choke for the Beretta Mobile choke system, same external dimensions as the Benelli, different bore/constriction diameter. The Tristar uses the barrel bore diameter of the Beretta, in the samples I have personally checked, 12ga and 20ga, there is up to .006" difference in barrel bore diameter, the Benelli being smaller.
Carlson and Trulock have a Tristar specific series of chokes for this reason. Look at the last 3 numbers of the choke constriction on their site, that is the bore diameter.
Personally, I would not order a choke until you test the extended choke that comes with the Viper, they are very well designed and thought out and work really well with TSS. I am currently using the factory sporting clays choke with TSS for ducks and geese, it is only .003" constriction over the bore. I had 2 duplicates made in black nitrided stainless, hopefully they will be here soon so I can test them out before season.
Carlson and Trulock have a Tristar specific series of chokes for this reason. Look at the last 3 numbers of the choke constriction on their site, that is the bore diameter.
Personally, I would not order a choke until you test the extended choke that comes with the Viper, they are very well designed and thought out and work really well with TSS. I am currently using the factory sporting clays choke with TSS for ducks and geese, it is only .003" constriction over the bore. I had 2 duplicates made in black nitrided stainless, hopefully they will be here soon so I can test them out before season.