This is the second part of a response to a reader who was asking about Tactical Lights. First of all I think everyone needs to be able to mount a white light on their Survival-Defensive Long Gun. You have to train with these lights just like any other piece of equipment. You can have an accidental light discharge which would give away for your position so you have to know the controls, switches and pressures down cold.
The weapons light world has come along way since mounting D cell Mag Lights underneath our M16's using hose clamps. But that's still a valid technique if you have no other equipment. In fact, I was teaching a weapons course to a unit which had M16A2 rifles without picatinny (aka 1913) rails. I gave them a familiarization shooting our guns which were mounted with various lights, but the white light for all of their night fire training can from the Mag Lights we mounted with hose clamps underneath their handguards. Hey the only handheld flashlight they had was the old Army issue Angle Head,...so guess what,....all the white light for their handgun night fire was using the Angle Head Flashlight.
One of the newest lights on the market is the InForce light. It uses a picatinny mount and the flashlight is pressed into the mount being held in place by grooves. I think this is to allow the shooter to rapidly remove the light for other purposes. The light is push button activated on the tail and has three functions: full on high lumen, full on low lumen and a strobe feature. Best use for this light is also with a pistol grip so that the off hand thumb can operate it. Strobe lights are popular and the idea is that the pulsing light disorients the bad guy. I did not find it very effective when tested on me. However the rapid dis-mount for this light is something worth considering if you do not carry other lights. Inforce light shown below.
Surefire is the King of Tactical Lights. Their M900 series Tactical light is a very high lumens capable flashight producing 125 to 500 depending upon the bulb you use. The flashlight is built into a picatinny capable mount with a hand grip.
Both the M900 and M900 with Turbo Head (you'll know it when you see it) are operated with a squeeze pad on the grip and a "dead man's" switch near the thumb. There are also two small LED's that are operated separably as a navigation light and are routinely used by teams to illuminate locks to be cut, or hinges/door knobs to be breached. The Surefire M900 with Turbo Head (higher lumens) is pictured lower right and the M900 with standard head is shown lower left.
The only problem I have with most Tactical Lights, and certainly all the weapons mounted lights, is that they use DL123 lithium batteries which are not rechargeable. You could buy a hundred of these for your Survival Stash, but the cost would be around $300 (minimum), and the fact they will eventually go bad is a deterrent. I have AAA and AA powered flashlights to replace my Surefires when I have no more DL123's, as I can recharge these batteries.
The lights shown above are all available from Brownells. The Urban Survivor would be well served to have the weapons light capability on some of his/her firearms.