The nut behind the trigger matters too.
I'd put that at or near the top of the list.
I see a lot of guys at the range with poor or no proper shooting technique. They seem to have a lot of trouble lining up their rifles for 100yd shooting. Sand bags and the use of them is often a revelation. If they seem open to suggestion, I loan them my extras and try to coach them. If they are "know-it-alls" who won't take advice, I let them bang away on their own.
