I contacted Wilcox with this question but they couldn't answer it for sure so I'm reaching out to anyone who has the RAPTAR LITE ES to possibly answer it.
I know the head is a Surefire M300 model scout light, but there is many variations in the head and models. I'm curious if a M300V head will work on the RAPTAR LITE ES series, and also the new Surefire M300 KM1-D (specifically because of the variable output option the light provides similar to the Insight WMX200).
Thanks in advance to anyone who has some insight into this matter and can lay hands on one to verify.

I don't have quite the same head, but I just gave it a try for you with a KM2 Vampire Scout head. It does indeed screw into the RAPTAR, but does not function the light. Interesting, as the head from the RAPTAR will function on the Scout body. Must be the way the contacts inside the RAPTAR body are built (with that metal donut on the head) that doesn't interface with the spring on the KM2 head. This particular vamp head is pretty chunky too, had to pop the laser off the rail to get it to screw on - would probably have issues with direct mounting unless you used the Wilcox riser that comes with the RAPTAR.

Let me know if you have any other questions - I love messing around with crap like this.

I wonder if the single battery (or even the new slimmer) version will work?

Im sure sales would have a huge sucess if the would have used a vampire head instead.

Yeah I'll have to make contact with Surefire and inquire why the heads won't interface. They might have a rough idea.
The vampire idea is certainly the best concept because it would cut down on the need for an additional light hanging off the gun for white/IR purposes. Specifically wanted it on a RECCE rifle build, to still maintain IR capabilities with less stuff hanging off.

Meh. The vamp heads have pretty crappy vis output. Much prefer the one that's already on it for more lumens and the built in laser illuminator for IR.