Re: HS Precision vs McMillan
McMillan A5 for me. The wide and flat foregrip makes shooting off a rest, large rock, tree limb, etc. easier and more stable. The action and barrel sit low in the stock, and is very stable. The extra thick stock butt padding is nice. I shoot from prone a lot and the butthook is nice for a rear bag.
The McMillian stocks have a rubberized feel to them which is more "grippy" than HS precision stocks, which some like and others don't. I personally like it more, especially in damp or dirty conditions.
But having said all that, if I was using it for hunting and did not shoot prone or bench, and all of them felt equivalent in hand...I would go for the lightest one.
McMillian ADJ M3A would be another consideration, since it sounds like you may not need the butthook.