Maybe the definition has changed over the decades, but I thought "keep" originally meant "upkeep" or "maintain" and "bear" originally meant "to carry into battle".
Also, I thought that "keep and bear" was a phrase like "cruel and unusual" or "necessary and proper", and was not meant to have separate meaning. Maybe it does today.
Well, that's the sort of verbal legerdemain that the anti-gun hysterics employ.
I believe no such thing.