Hey Texan:
I didn't realize I was echoing Stumpkiller so closely when I responded, but he's right on all accounts IMO.
If you consider the carraige, "shooting bags" are probably exclusive to a specific firearm and/or purpose. I'd imagine a man might have one bag for each of his weapons containing items specific to that weapon; thus, when he reached for his long arm, he might grab the coresponding bag. In that theory, I can see the practicality of a shoulder bag.
However. . . if you take any of those bags and shorten the strap, voila, you have a belt bag.
It's a pity, but far too many items did not survive from antiquity; consequently, we must extrapolate at times to create logical representations. This field of our is called "Historical interpretation" so it is up to us and our research to "interpret" the period as best we can. whether you use a belt bag or not, do so on artifactual and documentary evidence. it's OK to make a "Best guess" estimate as long as it's done with careful thought and research.
There's just not enough evidence to back patent black-&-white conclusions.
Proper interpretive displays require the right mix of intellect and imagination more than mimickry.
Whew, I haven't been this high up on my soapbox in a LONG time, anyone got a ladder?:redface:
Good luck on your search, and let us know what you come up with.
Cheers!