When Zack at Old Dominion Custom Rifles barreled my 222, he asked what barrel length I wanted. I had him thread it for a can, so I said: How about 22.2"?If group size is the number one goal, 22" is as long as I would go!
My 22" in my Panda 10.5lb LV, will shoot .1's when I do my part with 47 grain bullets at 3540 fps, 52 will group as good when I do my part and give me 3470 fps.
I can't recall seeing a top short range benchrest shooter using a barrel in any caliber longer than 22-22.5", most 20 to 21.5".
This partly to make wieght, but many use a wieght system in the stock to make wieght and keep the barrel shorter, in the sweet spot!
The cartridges they use with the faster powders needed to get full case load density, seem to prefer this length, and going longer gives no apreciable or relevant added velocity. Besides, absolute accuracy and bench manners trump anything a longer barrel could offer.
That's what he did. I love it.