In the special features, Kasdan talks about the Foley sound effects, making distinct sounds for the Henry, the shotgun, the pistols, etc. That segment played a couple of scenes with the blanks, then with the added effects. Sounded pretty good. Of course,I've never heard a .41 rim fire being shot.

Ever since you posted this - it's made me wonder if animals can tell the difference -
I've watched a lot of special features and they often talk about having to get the animals (usually horses) used to the gunfire.
Now I wonder if my dog would be skittish, alarmed, or surprised by real, live gunfire . . .
Bc - I watch so many westerns, (and even some war movies) my dog has no reaction to even extreme bursts of gunfire, or cannons,etc . . . and we're just 5 feet from the TV & I like my movies loud (can't believe I haven't got surround sound yet) . . .
Your topic has even made me wonder if the movie professionals who rig all these blanks can tell a difference ??

I wondered, since I can usually tell if a Western was made by Columbia, because the reports from the guns are always the same (even going back to the Three Stooges shorts!)
Also, to quote Gunnery Sergeant Highway tells his men in "Heartbreak Ridge, "This is the AK-47, the preferred weapon of your enemy. It makes a distinct sound when fired at you!"

that is interesting to think about - movies use 'blanks' when firing - but thet sound real - at least I can say that reports in movies are pretty much exactly like gun reports I've heard (lot of hunting and squirrel killin' goes on 'round these parts)
; )