I learn how to shooting at targets off-hand,kneeling,sitting,prone in the Marines. I also made the entry level shooting team with the 4th Marines in Hawaii and I made the landing at Chu-Lai with the 4th in 1965.
Big different target and the real thing.
I look at those pictures of guys standing and shooting and that's great for targets. If your up in the high country hunting carrying a pack or walking around hunting is someone really going to have that kind of time to stand like that.
I never once after getting out of the Marines ever use a sling as a support to shoot a rifle. I do agree with the one poster about clay bird shooting and I shoot more off-hand like that hunting. I've shot Silhoutte again that's target shooting vs walking shooting PD off-hand.
Have to stop and think about this. What would the score be like for the high power shooter if you took all those padded jackets,gloves using the magazine as a rest,sling or cradling rifle in palm of hand or their body as a rest for elbows.