Some extra thoughts of mine for your consumption:
The pre 1860 original trigger guards I have examined over the were all thin, well under .125 in thickness. The front and rear areas were rounded of course to a sharp edge with the bow rounded as well but not to a sharp edge. The very late HB guns I've seen were thicker appearing however. When I made Trade Guns using Curley's kits many years ago I always spent extra time trying to achieve the thinner look. I believe his trigger guard supplied was 1/8" material that allowed opportunity to file away the unwanted excess.
Charles Hanson's The Trade Gun Sketchbook and Pryor MT. Bill's Whately 1770 and Barnett 1830 books describe the specifics very well and are worth having in your resource collection if no original is accessible.
If you want to follow an accurately described copy or a general trade gun amounts to the effort you wish to apply to achieve the details. I've built both and most times details are mostly unnoticed and I need to pridefully point them out. Originals were accomplished by hand work and thus variance in many details is notable. Generally the Native populations demanded a few important details calling for small wrist size, barrels that don"t burst, bore size around 24 gauge, shortened length, knot free dark color stock, locks that don't freeze, and the guard bow large enough to admit two fingers inside mitton during cold temps. I've noticed they accomplished the bigger bow of course but then mounted the guard whereas the trigger was too centered or forward for easy two fingers use. That detail is a must for me!
Nice to see some NW trade gun questions. They were considered simple and cheap but had to be quality. That is early common sense!
Ray
