With a few exceptions, lights designed to be mounted to your pistol’s accessory rail cost significantly more than a handheld light of equal quality. Not only do they have to pack a lot of illuminating power into a small package, lights that mount directly to your firearm have to include a switch that is easy to reach.
The sensitive electronics must be able to withstand the recoil of a centre fire handgun. The lens material has to endure muzzle blast and fouling without breaking or permanently diminishing the quality of the beam. That’s a lot to ask, and it doesn’t come cheap.
Many weapon mounted lights will function perfectly over the course of a few practice sessions, but only the most rugged lights can withstand the recoil and abuse of being attached to a pistol for several thousand rounds. Consider how often you’ll want to practice with your light mounted to your pistol when making your choice, and assume that if you want maximum durability, it will come with a price tag to match.
Even if you decide not to keep your light mounted every time you fire the pistol, at the very least, fire 200 rounds with the light attached to ensure it’s mounted correctly and will not work its way loose under recoil. Also be sure to check that the light and switch still function after firing.
Finally, it’s not a bad idea to clean the outside of the light’s lens before storing the gun for emergency use.
Here are a few suggestions from Klarus Light to get you started. There are plenty of excellent lights listed here, always be aware that inexpensive lights typically cannot be expected to stand up to long-term use nearly as well as more costly designs. Remember the old addage, “If it looks too good to be true… it will probably catch on fire when you try to turn it on.”
Weapon Mounted vs. Handheld Light – What do you use?