Re: rear field rest??
I know what you mean about getting steady when sitting. I like that position for hunting, it gets you above the cover or over the knob to make the shot. I do pretty well with a tight sling, but I would rather use a bipod and that makes for a lot of movement as you say. Of course, I prefer prone and would like to have a monopod that attaches to the rear stud and has a very coarse thread for height adjustment. Now, when out prone, I just use my off hand under the rear. It's not ideal, but it will suffice.