A few folks pointed out that my lineup of Red vs. Blue costumes were inaccurate because Caboose (the taller blue guy) was wearing the correct MkVI helmet and he was supposed to be wearing the wrong Mk5 helmet. They were right.
In all of my searching, the best looking version of the H3 Mk5 helmet that I can find is still the model made by 405th user "flyingsquirl" for building with the Pepakura software. While I was in Afghanistan, I actually ended up building this particular model. Unfortunately, I made it way too big and ended up giving it to the driver assigned to my office, a Canadian Army Master Corporal who put some TLC into it and ended up wearing it out and about* while he was still in-country:
I built a smaller version as well, but then I decided that the proportions were still off and I didn't want to mess with the paper helmets anymore.
Fast forward almost two years and fortunately, through a ridiculously convoluted process of file conversion, I am now able to cut that model into slices that Lopez the Robot Whittler could cut out for me. Here's the four slices that make up the top of the helmet cut out in MDF with a coating of epoxy to harden and seal them:
Here's the other slices for the sides of the helmet attached:
As you can see, I made a significant mistake while slicing the model and ended up with some big gaps at the chin and a foreshortened nose. Fortunately, it still fits:
The next step will be a lengthy process of filling the gaps and building up the nose with some Bondo. Then sanding, filling, smoothing, and shaping before I finish cutting out the faceshield area and adding all of the little details to the back of the head.
Stay tuned. I'm sure I'll write updates about this build on a rare and intermittent basis...
*This photo was not retouched at all. That goofy bastard actually went walking around in the mountains of Afghanistan wearing a paper helmet that I made.