I've been lurking and following with interest tuning methods for years, even tried it myself (although not being a BR shooter). What I've never seen so far and am very interested in seeing is a validation of the method.
Let's take Fred's example he so graciously provided. I would like to see a follow up card with all groups shot at his best setting and another card with all groups at a not so good setting. Average the cards results and see if his best setting wasn't a fluke small group as to be expected from a series of such small sample sizes. Worded differently, what is telling us that what we are seeing is not 'noise' we would get anyway from that particular lot of ammo?
I believe tuners work, I just don't believe in the methodology. My rifles went several times to ammo factories (Eley, Lapua) to select batches of ammo but I am still not completely satisfied with the info provided for decision making. For those selected lots I cannot improve upon through the tuning I did, which simply might be from my own shortcomings (lack of benchrest skills).
The above is not to be interpreted as negative as I am genuinely interested in seeing some evidence to the contrary.
Best,
Gale Stewart
Quebec City, QC
Canada