I think Bill Larson hit the nail on the head, regarding sniper rifles. Especially LE rifles. You don't care how it groups, you care that the first shot goes where its suppose to do.
That's exactly how I zeroed or checked the zero on my rifle. I'd take it out and shoot it one shot a shot at a target, and used it. Next day, hopefully under different conditions, I'd fire one more shot at the target, do this for several days and do it every time I went to the range. Only counting the first shot if I shot more then once. I never shot it clean in this manner. If I cleaned it, I shoot several more rounds, put it back in the case, back in the trunk of my patrol car and a few hours later I'd get it out and fire one more round to make sure it still shot where it was suppose to.
Hunting rifles are different. No since in shooting more then 3-5 rounds, if you need more while hunting then you have other problems besides the rifle. I hunt with Model 70s, they are zeroed, to check them I have gongs the size of the vital area of an antelope (smallest animal I hunt). I have them set up at 100, 200, and 300. To check the zero I shoot one round at each using the kneeling position (my weakest position when hunting, I hardly ever shoot standing while hunting). I really don't care how my hunting rifles group at 100 yards from a sandbagged bench positions. I'm more interested in how it shoots from a setting position in the prairie, normally while I'm setting on cactus. Seems to be the law around here.
Target rifles require 20 shot strings, so I shoot 20-30 shot groups.
But I don't do this from the bench. On the sniper rifle I carried, I'd shoot it over the hood of the car, slung prone, or kneeling, or setting. Best shoot in the same place.
Same with hunting, prone, kneeling and setting, all in the same group.
Target rifles, setting, rapid fire, prone slow and rapid fire. And standing.
Shooting from the bench tells me nothing about shooting standing on my hind legs, or the other positions.
Think about how you are going to shoot in the field, be it hunting, target shooting, or what ever. In your same group, take a few shots in each position to get an idea of what your shooter/rifle/ammo combination groups will be.
