NateDog (or anyone else interested),
An AR shooter might do fine with that position, but you're going to find out in short order that your elbows are going to move on the first shot. Take a look at the picture below--see how I've got the back of my left elbow on the front of my knee? When the rifle recoils, my elbow will be supported by my knee. It will be pushed into the knee instead of being driven off of the knee.
Same goes with my right elbow. I've seated it in a place where it will be supported by my knee when the gun recoils. You will need to build a recoil-resistant position.
I am a somewhat tall guy, 6'1", and when I shoot with crossed legs, I have to choke way up on the stock to get the muzzle out of the dirt. I also end up with about the same amount of cant that wanderinwalker has in his picture above. I'm not opposed to canting the rifle, but the amount I had was inconsistant from one day to the next. To correct, I had to put on between 3 and 6 clicks left windage (depending on how much cant I ended up with on that day). When the gun recoiled, I'd totter back and forth like a Weeble Wobble.
I now use a modified crossed ankle position--my right ankle under my left calf. This does a bunch of things for me. I get a lower position which makes it a lot quicker to recover from the recoil (important item with a .30 caliber rifle). My body is more aligned with the target and the tendancy for my elbows to slip is a lot less. Finally, I now have just a little cant (maybe 5 degrees), and I use the same 2 clicks left every day. It's consistant.
Ty