I have considered it. Take a .50 cal can and put pistol and rifle ammo, a cleaning kit, batteries for the optics, etc. I finally decided not to because I used soft sided bags for stay in the fight gear and figured I could use ammo cans for single caliber.
The only other thing I would say, is that maybe you dont need a full .50 cal can if space is at a premium, maybe .30 cal cans would be enough.