This clueless obsession with the bench rest is depressing. A High Power shooter competes with a sub-MoA rifle, uses iron sights, shoots out to 600 yards and probably never bothers with a bench rest. I've seen countless hunters, who probably don't know what MoA is and will never shoot past 200 yards, never shoot on a range from any position off the bench.
I'll shut up and let Jeff Cooper take it from here:
Having nothing to lose, I am going to climb out on a loose limb and make a horrifying statement.
To wit: group size is spinach. Well, wash my mouth out with soap!
To a large number of smallarms enthusiasts in the world, group size is everything. If that is the way they want it, that is all right with me, but I must say that these people are devoting a great deal of attention to an essentially trivial matter. Certainly a very accurate rifle - or pistol - is a satisfying instrument to own and use. Whether it makes any difference in practical application is another matter.
Consider for a moment that group size is normally measured by group diameter from the impact centers of the two widest shots in the group. Consider further that even if that is a good measure, group radius is of considerably more interest, since group radius measures the distance between the theoretical point of aim and the worst shot in the group. And let us further consider that in any given group the majority of hits is likely to be located in the center of the group, so we can further cut down the "range probable error" to one-quarter of group diameter. In no case do we know of a man who can shoot well enough to appreciate that.
I was told recently by a colleague that he was attempting to do some head-size groups at 500 meters coming up summer. I responded that I had once shot an ornamental 500-meter group with an SSG, using 1962 Lake City Match ammunition, but that since I had shot it from a bench it did not really count.
I did not wish to hurt his feelings, but I do wish to point out that what the shooter can do from a bench is no measure of how he can shoot.