It's not a choke, it's called a "tuner". It allows you to match the way the barrel vibrates to a given load, rather than changing to load to match the way barrel vibrates.
It works well, although there is a fair amount of setup for a given load. So it makes sense IF you plan to use one specific load in the rifle. You'll shoot up a fair amount of ammo if you change around a lot.
Most BOSS rifles come with a muzzle brake weight, which has the advantages (reduced recoil) and disadvantages (hellacious noise) of any muzzle break. Browning does sell the a non-muzzle brake weight as the CR version.