I resharpen my rage 2 blades with one of those hand sharpeners Smiths makes. I just picked up a bohning broadhead sharpener to use much the same way. It works really sweet. Deploy the blades, a few licks on both sides, and you are ready to go again after a kill or a miss. I always try to test mine on shaving and touching a rubber band to it. This sure as heck beats buying replacement blades all the time.
It matters not the weapon nor its caliber, rather the caliber of the one who wields it.