Ric,
I certainly don't have a rifle or load that shoots without error and as the nut behind the buttplate I struggle with consistent bench technique not to mention correcting for wind. But perfection isn't necessary to check if sorting by weight (or any other variable) is improving your groups.
I am sorry that I didn't write more clearly. I compared lots of pairs of five shot groups not 100 shot groups. in my enthusiasm I also exaggerated. I should have said a hundred or more not hundreds of pairs.
I always shot at least a pair of groups at any one trip to the range. One with uniform weight bullets and one with either unweighed bullets or the groups composed of light and heavy “culls. Sometime I would have enough for several groups of each and I would always alternate so factors of fatigue, changing conditions, bore condition, etc. would have as much chance of affecting one group of the pair as the other.
I then averaged the groups with weighed bullets and compared it to the average of the groups with unsorted bullets or bullets sorted to produce the worst variation. I found no difference in the two averages. I believe it was reasonable to conclude that my weighing and sorting was a waste of time.
These pairs were shot while I was checking variations in the powder charge or some other variable but both halves of every pair were identical --except for the weight sorting or not. So checking for the effect or lack thereof of weight sorting was during shooting I wanted to do anyway -- sort of a by product.
The rifle and load I was using was averaging about one minute of angle for the five shot groups so with a more accurate rifle and load maybe the weighing would have helped. This was also with 22 caliber bullets. Maybe for larger bullets the dreaded air pockets are more of a factor.
So I am not claiming that my results hold for larger calibers or at ranges over 200 yards or for much more accurate equipment. That is why I would like to see others do some testing to check out the wider array of possible situations. Maybe weighing makes a difference for some situations but we will never know unless somebody systematically tests to find out.
John