Somewhere in my house is a shooting book and in that book are the results of lab tests done on primers, some years ago. Very extensive lab tests were carried out on all current primers. One thing tested was the difference experienced in the "fire power" of the primer, in consideration of how hard the firing pin hit it. They discovered that a hard hitting firing pin resulted in a hotter primer, while a weak hitting firing pin resulted in a weak primer firing.
Bottom line was the strength of the firing pin hit, made more difference, than did the type of primer. They stated that a magnum primer hit with a weak pin, had less heat and duration, than did a standard primer hit by a hard hitting firing pin.
I think this accounts for people thinking the cold effects the primer. Rifle actions have to be either thoroughly cleaned, then used dry, in cold weather, or some type of lubrication that is not effected by cold. If the firing pin barely fires the primer, it will be weak, regardless what primer is used.
I personally saw the method used by the old time meat hunters and trappers in severely cold winters in northern Saskatchewan. At the start of cold winter weather, they thoroughly cleaned their rifle actions with kerosene, then used the rifle dry, until spring. To get away from the sweating of bringing a cold rifle in the house, they had a simple solution. They never brought the rifle into a warm room all winter!
Most houses or cabins had a cold porch or shelter over the door, of some type. Walk up to a homestead house in the winter and the first thing you would see, would be a 30-30 hanging on the wall, outside. As a point of interest, it would have the magazine full of shells and likely one in the chamber, also.
One more thing about magnum primers. Magnum primers didn't come into existance until the early 1960s. So what do you think the shooters used for all those years prior to that?
