What's the consensus on load development and testing in freezing temperatures and how it translates to use of that load in summer weather? In particular, 22lr and loads using IMR4227.

Keep the box of 22LR in a pocket....

I shoot a fair amount of biathlon 22 LR.  For the most part the Biathlon is more accurate in the summer than regular 22 in the winter. Having one for each is not a bad idea.

For the most part, 4227 is pretty temperature stable, but the problem is reduced loads and bullets that really aren’t that aerodynamic, low BC’s, have their own problems in cold weather.

Losing 1-2 fps per degree of temp drop is not all that uncommon. So when you have a shooting season that can have more than 100* of temp swing, you could have a 10% velocity swing due to conditions and muzzle velocity.

Places like Montana have their own problems. Montana holds the records (lower 48) for biggest spread between record high and lows, about 190*. Largest change in both 12/24 hours and the fastest, largest temp change of about 60* in something like 7 min.

Kinda makes it fun.

-24 right now where I live. I should go out and test some ammo. I should.

I got a new to me Remington Model 37. Shot it indoors at 50 feet. Got nice 1 hole groups. Took it outside at -4F. Shot the same ammo at 25 yards. First 10-15 shots were grouping nice and tight. Then ZING a wild flyer. I pulled a round out of the box, and it had A snow flake on the tip of it.I got it too close to my lips trying to blow the snow flake off. My lips stuck to it. If you shoot a .22 with a lip patched bullet, it will NOT go into the group.

The ones after it did not either. My guess is the lube froze. Gonna test with plated bullets, and see what happens. Also gonna try putting my ammo in a cooler with a heat source.

Where I live, if you can not shoot cold, you can't shoot outside very often. My experience is you will loose some velocity. OK, you knew that. The issue to work around will be your lube.