There are many more options out there for long gun lights than there are for handgun lights. While this means more choice, it can also mean more confusion about what you need.
There are essentially two basic categories of long gun lights: Dedicated weapon lights, and mounts that let you use general purpose tactical lights.
An example of a dedicated weapon light is the 9 volt Surefire you see in the picture.
It attaches to the rifle via a dedicated throw lever mount (you can get one with a thumbscrew mount which is preferable because the ARMS throw lever mount pictured is absolutely terrible) and it has a remote tape switch activation. It’s a very good light, durable, reliable, and more than bright enough for any general purpose carbine work.
It is also heavy and expensive. I purchased the pictured light for over 300 bucks several years ago and other than the fact that the stinking mount falls off the weapon entirely on occasion, it’s been a good light. (if you want a good throw lever mount for this sort of light, buy a LaRue). Recently, however, I saw that Larry Vickers was using a Surefire G2 mounted to his rifle with a VLTOR mount and I started thinking.
The G2 setup described costs less than 100 bucks even if you replace the standard G2 element with an LED upgrade.
It’s also a good bit lighter than the big Surefire, takes up less rail space, and doesn’t seem to have any real disadvantages in actual use.
I decided to give it a whirl myself and since running it in dedicated low light training I’ve found it to be a wonderful option. It’s effective, reliable, and cheap. What more could you ask for? One note of caution: If you want to use an incandescent G2 in this sort of setup in a weapon bigger than 5.56, you should invest in a shock isolated bezel to keep from constantly blowing out lamp elements.
Are there other options? Sure. The Surefire X300 is also very much at home on the rail of a carbine. Pentagon makes some nice carbine lights that seem to perform well.
Because there are so many options you shouldn’t have any issue finding something that will fit your budget and your needs. My only caution would be to remember that our earlier discussion about the lumens you want on a tactical light also applies here.
You don’t want to have a face-melter on your carbine any more than you want one on your handgun or in a handheld light. Anything from 60 to 100 lumens is preferred for a carbine light that will be doing work indoors and outdoors.
If you won’t have to go into enclosed structures and you have lots of money then you can buy one of the super-high lumen Surefire anti-aircraft lights if you want.