you should take a look at the Flashlight-reviews.com. I believe the light is rated there with a value given for "overall output" . Then if you read further there is a factor that Output/factor= lumens. (There is a different factor for incans and leds )
Just under 40 lumens on fresh batteries, but Mag's "energy management" regulation isn't quite up to spec, so the light averages most of its slowly declining runtime at around 66% brightness - roughly 26 lumens.
check out the mag incandesent stacked against various mag dropins. pretty sad. it will take you a minute to find the mag incandesent. (unless you start looking in the bottom left corner) lovecpf