Now this is exactly why I just read and almost never post.
I said almost guarantee a one hole group. The reason I said that is because it has in every 26" barrel I have tried it in, or know of, that it was tried in, including a couple of friends rifles. I'm not the whiz kid that came up with it either, I found it in a rather large forum dedicated to long range shooting. You've probably been on it also, especially since they have been shooting the 208 AMAX for distance quite a few years now.
A 26" inch barrel has alot to do with it since he asked for loads for a MOD 700 Varmint. They, by the way they have a 26" barrel. I posted what I did because said load, works very well in a 26",pretty good in a 24". It does not seem to do as well in a 20" barrel. Again, this info was picked up from others who have had the same results.
I won't disagree with you on a 20" barrel vs. a 26" as far as toting around, however my 24" barrel Accuracy International weighs more, and is harder "to tote" than my 26" Mod 700 Varmint was, which also had an Acc. Int. stock on it. I wasn't trying to talk him into a 26" barrel, he already has it. I'm also not trying to talk you into one. As a matter of fact I've had aLL 3 lengths and I like them all for different reasons.
I also never stated that there is an accuracy problem with a 20" barrel. I have found them to be extremely accurate.
I haven't tried the 208 Amax's, so I can't say one way or the other but there is definately more than 10 fps difference per inch of barrel in the loads I've chronographed out of numerous barrels, YMMV.
So, in conclusion I was just trying to give the guy a load that has worked well for me and others in a 26" barrel, not get into a pi**in' match.
Have a good one.