or the Wipac Crystals, seen these on a ex mil round me, he has the same lamps in as me on standard lenses, but the beam is Sooooo much clearer/brighter.
IMO, from what I have read, a beam controlled by the reflector (ie the wipac crystal or the diamond eye hutch mentioned will have a better beam pattern/range.
those that use the lens to control the beam loose some clarity and range as some light is lost through internal reflection.
Crystals can be had for £30 on ebay (wipac copies, still glass lensed,and look ok)