I'm a little puzzled when I hear a request that a light can "throw" some particular distance. The light beam doesn't just go out some distance and stop -- it becomes weaker and weaker as the distance increases, but it keeps "throwing" its beam to just about any distance you choose. What you need to specify is just how bright you want it to be at the specified distance -- otherwise, you can't put a single number on "throw".
The best "throwing" single LED flashlight I have is an MRV with the emitter replaced by a Q5 bin Cree, running from 2-RCR123 Li-ion cells. I measured its main beam at just under 30,000 lux at one meter. (The actual measurement was made farther away and extrapolated.) This means that at 100 meters, it would illuminate objects with a brightness of 3 lux. According to
Wikipedia, a full moon illuminates objects at about 0.25 lux. The MRV produces this much light at about 350 meters. Starlight is about 0.00005 lux; the MRV puts out this much illumination at about 25 km. So in theory at least, a person with dark-adapted eyes standing in starlight could detect that an object was brighter when you shine your light on it from 25 km (about 15 miles) away(*).
One rather arbitrary definition of "throw" is the distance at which the main beam illuminance is 1 lux. By that measure, the MRV "throw" is 173 meters. But this doesn't mean that you can light things up at 172 meters but not at 174, any more than any other arbitrary definition does. So how far does the MRV "throw"? 100 meters? 173? 350? 25,000? Take your pick. The answer is just about anything you'd like it to be.
(*)I'm sure there are practical limitations to this, such as additional attenuation due to particulates or moisture in the air. So in practice you probably wouldn't be able to detect the light shining from 15 miles away. But maybe you could from, say, 5.
c_c
