@kyoto kid: Hand-loads are proxyable with a custom file until I can spend time to implement it in a way I'm happy with. I don't want to implement them as gear entries like that because I don't want to pollute the gear file with a bunch of variants of each ammo type.
@Longshot23: Depends on the thing we're looking at. Chummer stores the whole object in XML, while Herolab (from memory) only stores a name reference, which they presumably rebuild from their datastore on load. Things like skills are handled differently though, as it seems the whole value is stored, including points from other sources. Mostly it's just to cover our bases and encourage you to double-check everything is correct.