Along with the venerable .222, I have had multiple .25-06 rifles putting bullet on bullet, seems to me this cal has laurels. 
And sir you proved a point with this post. Accuracy is holding tolerances, Square mating surfaces, great ammunition ,great scope, great trigger and a talented shooter.Some years ago i read in the Benchrest Shooting book that a custom built BR rifle, chambered in 30-30 with quality cut rifled barrel in side by side tests with a 6mmPPC BR rifle shot equally as well
But if the variable wind hadn't blown 'em all thru the same hole, it would've been a 4" groupMy experience of different calibres is somewhat limited, but of the few I've fired the 22-250 impressed me most for accuracy. I'm a pretty poor shot myself, so when I placed 3 shots through one ragged hole at 100m in a howling gale and pouring rain using a rifle I'd never handled before I was astounded!
Well that thought did occur to me, I must admit! To be honest, I was struggling to see the target because of the rain. But nevertheless, 3 shots through the same hole left me mightily impressed with the accuracy of the 22-250.But if the variable wind hadn't blown 'em all thru the same hole, it would've been a 4" group![]()