ML,
I have seen a good video for position shooting. This was maybe 10 years ago and I don't know if you can find it.
I don't know the name of it,,,however, the film was hosted by Sgt D.I. Boyd and it featured David Tubb and the current (at that time) Service Rifle Champ. They demonstrated the three positions use for rifle competition, offhand, sitting, prone.
With both the M14 and the bolt-action rifle. It was a good video.
If that one can't be found,,,,maybe David Tubb has a DVD on shooting....he was won the NRA Camp Perry Matches 6 or 7 times.