Guys,
I just checked the tail cap switch from my Mr. Bulk LGI and it is a 5/8"x24 thread wheras the Kroll and McLux and Arc and I think there's another *older* flashlight company who all use 5/8"x28. The thread pitches are NOT the same so you will be cross threading and likely find parts that have, as a friend used to state: "bound up and went doggo".
A better switch is easy to design. I have one sitting on my bench as we speak that is about 50% completed. No point in continuing unless some body or group of folks are willing to pony up the 15 to 40K required to pay for the tooling and initial run.
- Don