Thanks for the input so far!!!
Dave I have to agree about finding a period lists of weights for leather. The two items that I am working on are a Gunners Haversack and a Tube pouch, both of these are used in the artillery. What is interesting to me is that the haversack is lighter weight and the tube pouch is heavy based on your info. I would think that the Haversack would be a thicker leather because of the weight carried in it. For those that don't know the Haversack is used to carry the powder and projectile from the limber to the cannon. The tube pouch only holds the lanyard, vent prick, and friction primers, which is a fraction of the weight carried in the other.
Thanks again
Bill