Fulton MX-991/U “Moonbeam” Hurricane Light Build/Mod: Moonbeam No More.

After much delay, I finally have finished this write up, 2020 sucked for most all of us, and random BS got in the way of this for far too long, but it’s 2021 now and time for this post.
Special thanks to @Boker55 for providing me with the MX-991/U for this mod.

To begin, this project was inspired by my fondness for the old standard issue MX-991/U flashlight, known by many as the “Moonbeam” due to its weak beam output, this iconic piece of military equipment has hardly been altered in its design since the 60’s which even then was just a slightly updated WW2 design.
I resolved to improve the old “Moonbeam” with modern LED technology and see if I could make it into a practical light for modern applications.
Now there’s no way that the old “Moonbeam” could be made into something like a high output Streamlight or Surefire tactical light, its plastic body would be hard pressed to handle the heat, and it is too large and bulky to really serve well in the roles such a light is expected to fill, so instead I decided to work on the “Hurricane Light” concept, emphasizing moderate output and long battery life, important factors for a light which will be called on for sustained use during a hurricane or other disaster, this is aided by the high capacity of the D cell batteries.
After much research, I opted to replace the old PR-4 format incandescent bulb with a Nite-Ize ‘high power’ drop in LED replacement, which strikes a nice balance of useful output to battery life, and sits well inside the reflector assembly.
With this new LED, the “Moonbeam” boasts a very capable 50+ lumens out the front, and has a long enough runtime that I’ve had a hard time quantifying it, suffice to say that with a couple spare sets of batteries you’d be set for a week plus of intensive use.
The beam profile is a nice intense hotspot, with good usable spill outside of it, with a practical reach of about 50 yards, nothing groundbreaking but far above the capabilities of the original, and plenty adequate for most uses.
Overall this upgrade breathes new life into a classic, and will serve well as a utility light, or for emergency use where runtime and durability are the main requirements.

One additional upgrade I had intended to make was a set of optional AA adaptors, which can run 1-3 AA cells in parallel, ideal for scrounging batteries from other sources since they can run the light on just 2 AA cells, or nearly equal the mAh capacity of 2 D cells by using 6 AA cells.
This however has been delayed by financial restrictions, and the uncertainty of shipping from outside the CONUS as of late.

The old “Moonbeam”:


Disasembled:


The drop in:


Beam shots: