[Bruce Em]

Depends on the load and the wad; a marginal load will under perform or even fail in cold weather. Its all a function of proper pressure to burn properly.

regards

 

[mtimney]

I'm shooting a winter league in my home state of New Hampshire. We had a day a few weeks back with the thermometer at about 10-degrees. I'd left my shells sitting outside in the cold for about an hour before I shot...and the first two boxes of shells I'd loaded with Red Dot and Green Dot, using Winchester primers, weren't igniting very well. I put the other boxes I had inside to warm up for a bit and they all worked perfectly. The cold seemed to be the culprit.
Mark T.

 

[sptnclays]

I switched to federal primers. Problem solved.

 

[Joe Potosky]

It was once recommended to keep your shells in a cooler when at the club and only take them out just before you need them.

Also, as suggested, keep them in the house not the garage or vehicle. May take half a day for shells to reach room temperature (someone here did a test years ago).

Saying all that, never had a problem with 700x, Winchester primers and claybuster wads.

 

[Stl Flyn]

"It is pretty common, I believe the cold weather affects the wad's ability to seal and allows powder migration around it."

I second this opinion. If you take a flashlight, and backlight through the hull, you will see a migration of powder past the powder seal. The more powder that goes past the edge of the wad, with vibration and such, the less powder is going to burn. When the plastic wad is cold it contracts even more, then add the fact that the seal around the edge of the cup will not as readily expand out to create a seal of the expanding gases, thus creating less back-pressure so to speak. A hotter burning primer may help. You will really notice this happening in the larger bores, for the same reasons.