The Richmond Arsenal oversaw the production of tens of thousands of knapsacks over the course of the war.  The majority were made via a system in which the Arsenal would complete the assembly of contract-made bags by adding loops made from black dyed scrap leather from saddle production and pre-made sets of undyed leather straps made by the Clarksville Ordnance Harness Shops.  This example is copied from one of several surviving originals by L.D. Haning, and would be a great addition to your Bedford Artillery impression (and ANV impressions in general).

Richmond Knapsack - Sharpsburg