El Deguello ----- Your one shot group is close to something I do when I have established a finished load with a rifle that I plan to take where weather can be "iffy". I shoot one shot into a target with a fouled barrel after recording the temperature. I put that target aside. Then I repeat that under another weather condition later. Then I superimpose those targets at the end of the year to obtain a group of single shots at temperatures ranging from 0 to 95 degrees. That group is my one shot group at any temperature I may be hunting at with that load. The results may supprise you, but it also gives you a range of where that cold barrel bullet it going, which in my opinion is what the hunter of game needs, much more than three, five or ten shot groups shot with hot barrels. That first shot is maybe all you will ever get at the trophy of a liftime. I like to avoid those "OH SHIT" situations, and make them into "Hey that shot was gooder'n taters and better'n snuff" situations. Good shooting.