If you expect a flyer, you'll more likely get one.
It's a mind trick, but it does exist. It's about confidence and its subconscious effects. Basically, if you think you'll miss your mark; sometimes you can't hit it. It's a real thing.
Shooters believe they are supposed not to know when the sear will break, and for some that's true, especially when they're newer at it. But eventually, we start failing to fool ourselves about that sear. A controlled squeeze does not need to mean absolute surprise. What it does require is the discipline not to flinch when it's now-Now-
NOW due to break. When you can get to that stage, you're golden; and that is definitely attainable.
Also, sometimes a charge weight is at the top end of the node. As the barrel heats, the later chambered cartridge's charge gets heated more prior to discharge, and the load falls outside the node; especially on the hotter days. You could try reducing the charge by a couple of tenths and see what happens. Small groups are nice; consistently smaller dispersion under all conditions is better. I don't want to cringe when firing that first shot on our Southwestern 105-110 degree afternoons.
The cartridge is a heat engine, what you get out is all about what you put in; and when the charge heats, there's more energy contained in the package. It's not that complex.
Varget's a great powder, even in the 6.5CM or in the 260 that I shoot. But the right charges do not usually result in the ideal compressed charges that I prefer to use. Because they don't fill completely, there can be issues with how the charge settles after chambering. Differences create dispersion. For that reason I use slower powders like H-4831SC for the heavies, and H-4350/IMR-8208XBR for 120gr and down. They fill the cartridge more than Varget, and could be more efficient in the longer 28" barrel I shoot.
I'm doing experimental load development with the Speer Gold Dot Bullets. What BC deficit they may have is compensated for by very effective terminal performance. That could come in handy for that day when the target isn't a piece of paper. LE seem to like them, too. I'm testing 90TNT, 120 Gold Dot and 140 Gold Dot in my 260.
Speer Data.
I have a trick that reduces cooking the cartridge.
Set up you rifle for the shot, but don't close the bolt until just before ready to fire. Until then, the cartridge rests half in, half out of the chamber; and there is very little contact area to conduct heat to the cartridge.
Obviously, I'm talking about single feeding.
Greg