As most of you already know, I'm a Malkoff fanboy so it should come as no surprise that I like using them as WMLs too. The wide selection of mounts for 1-inch body hand-held lights opens up many possibilities. :-)
I am also a proponent of the KISS principle for ARs, and I strongly detest seldom-used "stuff" living fulltime on the handguard. I'm not an "Operator" nor am I LE that needs to clear rooms as part of my daily activities, so I have the luxury of keeping things pretty simple (and lightweight, and not bulky, etc.). That said, the ability to quickly attach (and detach) a powerful light has strong appeal to me. Since the light is not living on my rifle 24/7, using something larger and heavier is of little consequence to me.
The (former) fulltime resident Malkoff/Arisaka Scout 300 clone shown below weighs only 3.2 ounces and produces 750 lumens/20,000 lux;
Lightweight and reasonably powerful, I think it's a excellent setup - providing you don't mind a light living on your rifle 24/7. In another thread I posed the question of how often are WMLs used by civilians for practical purposes, and the response was for rifles dedicated to defensive purposes and night time pest control. That makes total sense, but an AR is not my primary defensive arm and I do not conduct any pest-eradication with a firearm.
Which brings me full circle back to where I started years ago in terms of ARs and WMLs: I want the ability to quickly attach a WML when needed, but don't want it living on the rifle. If that light can be more powerful than the usual weapon-dedicated light, and also serve as a useful hand-held light, that would be my idea of WML awesomeness.
Taking this approach, this is my BF(QD)WML setup for my rifle. It consists of a Malkoff Hound Dog 18650 (1,000 lumens/29,000 lux) attached to the port side of the handguard using a Vltor off-set scout mount;
When the rifle is stowed in the safe, it goes in with the light attached. When the rifle comes out for normal daytime range use, the light comes off, which for me is 99% of the time. Of course with it detached, the HD 18650 is an immensely useful light that can be dropped into a coat pocket or carried in a holster. The beam pattern of the HD 18650 is just about perfect for rifle use, a good blend of throw and spill. Below is the light riding in a kydex carrier and a spare 18650 cell in a waterproof Delrin capsule (the Vltor mount is dropped into a pocket or range bag);
Of course there are other Malkoff heads that can be used with this arrangement, including the M61HOT (740 lumens/20,000 lux) to create a smaller package.
As a flashlight nerd and wishing to leverage my Malkoff fanboyness even further, I will be making a change to the light very soon. Using the same MD2 body but with a pair of IMR 18350 cells, I'm going to upgrade to the Hound Dog Super head, which produces 1,700 lumens/75,000 lux. The HD Super head is 2.25 inches O.D. vs. 1.8 inches O.D. for the 18650 version, but there is more than enough clearance for it to fit. The pair of IMR 18350 cells will provide about 20 minutes of full output runtime, and over five hours on low (80 lumens). The HD Super is currently on back-order on the Malkoff site, but as soon as I have my fanboy hands on one I'll update this thread with my impressions and photos.
No doubt that arrangement will make the "BF" aspect even more convincing. Experimenting with this stuff sure is a lot of fun. :-)