I loaded some .223 with varget other day, and left them in the truck while at work, it was maybe 80F or so in there when I left. Strait to the range, found a good zero at 250 yards, packed it up.
Showed up at match this weekend, and I had left the ammo in the truck at the hotel, I usually bring it up to the room, but said screw it this time. Temp got down to fortysomething that night, I noted how cold the ammo was when loading my mags that morning.
First stage, targets around 180 yards. I was aiming 6 o'clock, and couldn't find a hit for the first 10 shots or so. I was sweeping left, and right, but when I moved high, I got a hit, cleaned the rest of them, and figure the temp variation was the only varible. Later that day we had a long range stage, so I loaded up some black p-mags, and put them on the dash in the sunshine, until the ammo was very warm and toasty. Shot that stage without a hitch, impacts were normal. So, there appears to be some variation with the varget, it's not the perfect stable powder I thought it was. YMMV.