I've designed a 3D printable Halo M6G Magnum pistol prop for fellow fans. Some light sanding may be required for optimal fit and finish.
Updates:

October 14, 2017: Recommended printing method added - For 1:1 scale on Prusa i3 Mk2/3, print as two separate halves (see reference image)
July 15, 2017: Added complete assembled file for convenience

If you enjoy this model, please consider leaving a like! I'm open to creating an advanced version with additional features - let me know in the comments if you'd be interested and what improvements you'd like to see.