Thanks to the proliferation of AR-15s with railed hand guards that cover or extend around the gas block, it has become more common than ever to mount a white light on your carbine in the 12 o’clock position (directly on the top rail of the hand guard). Mounting the light in this position isn’t a new idea, it is has just been made more practical by the way many carbines are being configured.
In this post, I want to address a few questions. Does mounting your light in the 12 o’clock position offer any advantages over other mounting positions? Does it come with disadvantages? Which lights and mounts work best for the 12 o’clock position?
Mounting a light at 12 o’clock offers several advantages over most light mounting positions, especially the positions that push the light out to one side or the other.
Use of Cover – Perhaps the biggest advantage is that a light mounted in the 12 o’clock position is optimized for use of cover. The light will clear cover while exposing as little of the shooter as possible when shooting over or around cover in either direction. If you must shoot under extremely low cover, you will have to roll the carbine anyway so shooting under cover is basically drama free. This is a distinct advantage over lights that are mounted to one side or the other which cause the shooter to have to slide out beyond cover a bit more to put any light down range.
Reduced Impact of Shadowing – Unless you mount your light so that the bezel is just about even with (or beyond) the muzzle, you will have to deal with some shadowing caused by the barrel and muzzle device. If your light is mounted at 12 o’clock, that shadow will be cast directly down. It only obscures areas of your field of view that are already obscured by your carbine. This is ideal.
Ambidextrous Activation – A light mounted at 12 o’clock offers the ability to easily activate the light with either hand. The light is on the center line of the carbine so it is equally as easy to reach whether the right or left hand is being used as the support hand.
Ergonomics – If your stance supports it, the 12 o’clock position tends to be a very natural position for the thumb of the support hand to reach. It falls somewhat naturally under the thumb, especially if you tend to use a high, thumb forward or wrapped thumb grip with your support hand.
Weight – The lights used for this mounting position tend to be fairly light weight and, in most cases, don’t require an additional mount which also keeps weight to a minimum. Many of the lights best suited to this position weigh less than 5 ounces and some weigh less than 3 ounces.
Special Equipment or Setup Required – The biggest disadvantage to mounting a light in this position is that it will usually require some special equipment and forethought to achieve. Most off-the-shelf AR carbines are not going to allow it. You will need an extended rail that covers the gas block/front sight base, an FSP style rail that wraps around the front sight base, or a bolt on accessory.
Unusable for Some Grips and Stances – The 12 o’clock light really only works if you grip your carbine out at the end nearer the muzzle. The light must be placed in front of the front sight which dictates that it must usually be placed fairly far forward. A tape switch may be used to alleviate this to a certain extent.
Reduced Sight Radius – You may have to move your front sight to the rear by a few notches if you are using a rail mounted front sight in order to have space for the light in front of it. This reduces the sight radius. As a rule, the farther apart your sights are, the easier it is to be precise but this is not nearly as big a deal as it is made out to be – especially since iron sights are likely your back up sighting system.
12 o’clock Lights and Mounts
Lights – The most common 12 o’clock light that is seen is the Surefire X300. It has a low enough profile to stay out of the way and a switch that is very conducive this type of mounting. The INFORCE WML is perfect for use on the top rail. It is also one of lightest options available at 3 ounces, including the battery. Users are also having good luck with the INFORCE APL. It is the lightest option on the list. The Streamlight TLR-1 works well for right hand shooters but is less ideal for left handed shooters thanks to its rocker style switch. The Surefire M600 and M300 Scout Lights also work very well even though they are rarely used. They can be used with either the tailcap switch or the tape switch in this position.
Keep in mind that your choice of lights may be limited by the method by which you are mounting it. Not all the lights listed here will work with all the mounts shown due to size constraints. As a general rule, any light that requires a flashlight mounting ring to be attached to the rail or mount will sit too high to be useful.
Mounts – If you don’t have an extended rail or an FSP style rail, then you still have some 12 o’clock mounting options. The most recent is the Midnight Mount from Mossie Tactics. It clamps the front sight base. Hahn Precision makes the Forward Light Mount which clamps to the barrel. Michiguns LTD makes the ILM (Ideal Light Mount) which does requires some modification to the front sight base.
In my experience, mounting the light at 12 o’clock is demonstrably better than mounting the light in other positions, but how much better is up to the user to decide. The various advantages and disadvantages must be passed through the filter of your experience and checked for compatibility with your shooting style. I encourage you to give a 12 o’clock mounted light a try.