I had an experience with Armytek flashlights. I own armytek predator. It is made specially for military and hunters. Body diameter is 1". This light doen't contain any moving parts and the electronics is filled with the special compound. Also in Predator there is one strong spring with the big cap to save battery minus contact from shock due to the larger area of the hard spring. As a result, there is more reliable rifle light design due to this strong spring with the large contact.