no idea .. my personal thoughts are that the reality is a barrel doesnt need to be 'clamped' in place with many designs and a barrel band doesnt give more accuracy .. the barrels actually do best free floating and the idea of a barrel band is to protect the barrel from being knocked out of alignment, in other words the barrel is just held centered in it, not clamped by it .. its a protector, not an accuracy solution ... most of the time ..