Some 10% died from unsanitary water. They had no idea back then that using the same water over and over again at way stations or using stagnant water caused cholera. The cure of merely boiling water was not known then. Next came accidental deaths from drownings at river crossings, wagon accidents and other injuries where infection set in. The number of accidental deaths from firearm’s would be darn small as many of these folks had fought in the War of 1812 and/or then the Civil war,and other’s had hunted since boys. Heck, this PBS station is a joke. Add Juan Williams to it’s lying crew.
I wonder if an assumption is being made that the toll of deadly accidents was largely due to weapons and then the calculated conclusion is being trumpeted, circularly, as truth. I agree this would be unlikely on that rugged and ready trail. Especially as you point out this is before modern sanitation and the advent of the antibiotic, which has rendered many former formidable menaces trivial.