There is no question that some of these old guns can shoot very well indeed.
However the target and the note bring up two rather important points.
1. That group was done with a hand load using commercial Sierra 168 grain bullets of far higher quality than any 7mm military ammunition used. Some military ammunition might be able to fairly well, other military ammunition might be lucky to stay within the 8 ring on that target.
2. Mausers in general have lousy sights. I would be willing to bet money that at
least the high and low shot on that target are the result of sighting errors, that or inconsistent shoulder to stock contact.
Different Mauser but gets the idea. Getting the top of the pointy front sight dead even with the top of the rear sight 10 times in row is hard, almost impossible. Left and right can be a little iffy too. Please note this is against a white background. Now try aiming at a man in brown or khaki color clothes in a wooded area (in shadow). Now do it in a hurry.
The barrel and action of many of these old rifles are capable of very fine accuracy, but the less than quality ammunition (compared to what is available after WW II) and the difficulty in getting a consistent sight picture (especially with less than 20/20 vision) have a significant impact on the performance of the rifles as a
weapon system.
BTW, more view through sights.
Please note on the guns with Aperture rear sights it is not necessary to align the front the sight in the back sight for anyting but target work, Just align the front sight and target. Eye doesn't have to try to focus on the rear sight.
View: http://imgur.com/gallery/ZM7IX