With a SureFire M3 or M4 and a 250+ lumen lamp assembly and an optic you can engage human sized targets easily at 400 yards.
With the M4 you get an extra batter and a 350 & 500 lumen lamp option.
I was making fairly fast head shots at 300 yards with my M24 once I knew where the target
was. Without sufficient levels of ambient light, you will not be able to ID what is in their hand or have facial recognition much past 150-200 yds.
See:
strategosforum.com/phpBBx/viewtopic.php?t=4104This light was mounted directly over my optic.
Here are few pics on bolt guns:
SureFire M4 on my M24 – Arms Mount
Laser Devices 6-Volt on my M24 – Arms Mount
My SureFire M4 on NYPD Sniper Rifle – SF Mount
Handheld or offset options:
If you want to have some serious reach out there and see capability consider a McCulloch HID X990 light. We call it the “God Light” in our low light sniper course.
Literally turns night into day at ranges you can expect to touch somebody with your AR.
Just Google: ” McCulloch HID X990”
A lower cost, lower capability option has already been tabled, that is the K-Wart/Wall-Mart portable/rechargeable spot lights. They work really well