Be mindful of your training

Not all Appleseed instructors are created equal. It is a volunteer organization, and this can spawn some nitwits who will teach you all wrong, and they will leave you thinking they know better.

Instructor "Mudcat" at my first Appleseed is an example of just that sort of thing. For the sake of documentation, here are the errors he passed on as being correct methodology.


Sling too tight
Mudcat advised myself and others to tighten slings - to the point of hands turning purple. He stated that we should loosen them between firing times, so as not to cause permanent damage.

The correct method, is just taut. A sling, properly adjusted, can be worn all day with no ill effects.

Over-tightening not only poses circulatory issues, but causes the shooter to have to muscle shots on target. This defeats NPOA and makes shooting accurately more difficult.

Over-tightening also shifts the rifle's Point Of Impact (POI). On traditional wood-stock rifles, the effect is less pronounced - often 1 MOA or less. On AR type rifles, and some others - where the sling attachment is directly touching the barrel - the POI shift becomes more dramatic. There are also reports of barrels being ruined by overly-tight sling shooting.


Proper support elbow position. 
Mudcat advised that the support elbow, in prone, should be 45 degrees to the side of the rifle. He stated we should try to get as close to the ground as possible with the rifle.

The correct method is to have the support elbow directly under the rifle. This props the rifle up, and allows the shooter to shoot over low grass, or short barricades. It is also much more stable a position.

Now, the upper arm of the support hand should form a 45 degree angle to the front toward the ground - with minor variation depending on the person's build and individual comfort. But Mudcat kept telling us to get it to the side, as it was the only way we could get closer to the ground.


Proper sling positioning.
Mudcat showed incorrect sling position - having me put mine on backwards, and actually putting my wife's on backwards for her.

Putting a sling on backwards reduces the effectiveness of the device as a shooting crutch. It also makes accurate shooting more difficult.


Conclusion
I would have, in my earlier years, admonished this "instructor" for the errors he was passing along. Additionally, his attitude, which sparked several others to leave, left a lot to be desired.

However, as I've aged and matured, I've come to realize that one should never ascribe malice when a simple excuse of stupidity will suffice.