I wouldn’t I’d instead run Burning Wheel with some sci-fi style lifepaths and coloring.
Many of the subsystems in Burning Empires don’t work for the scale and play that a “normal” RPG covers. Firefight expects small-medium unit engagements, everything relating to Infection breaks if you aren’t running an opposition force, and having a scene economy makes no sense if you aren’t working within a larger framework. I’d also argue that the non-color portions of the World Burner are also core to Burning Empires and totally pointless to a more free-form RPG: for a BW-alike I’d either do it as all color or use something like Diaspora’s Cluster Generation to make a group of planets to have my game. The stuff that is portable (and different from Burning Wheel in a meaningful way) is the Character Burner, the weapons table in firefight, Armor and Iron (the section for handling how armor protects you), the tech burner, and a few other minor sections like vehicals.
From BWG, pretty much everything works out of the box with the exception of the non-sci-fi feel of the lifepaths (also elves, dwarves, and magic). The game pace and scale is also a lot closer to what you’re looking for. For guns, Range and Cover with the addition of the ammo rules from Burning Sands will do you.
Not trying to spoil your fun or anything, but BE is really designed to only do BE and doesn’t do anything else without a lot of work.