Magnum primers for cold weather shooting?

[purple]

Yup, I recently worked up some handloads for my daughter-in-law's new Model 7 Rem in .243. Before going to the range I stripped and degreased the bolt. The interior, firing pin and spring were all coated with a fairly thick grease.

Weapons maintenance was always a big consideration in winter warfare training. The idea was to use minimum oil and NEVER bring a cold weapon into a heated tent (even up on the artic tundra) where moisture could condense on it and then freeze up when you took it outside.

 

[07blackwater]

All I use now is g96.

The internals get degreased then I spray some g96 on a cloth and wipe the parts with it.

I learned years ago that 'oiling' is bad in the cold. One time I tried to pour some gun oil on to a rag and it was like molasses. Last time I used it. I switched to tri-flow after that but, like I said, it's g96 all the way for me now.

When I'm hunting my rifle sleeps outside as well. Binoculars too. Keeps the optics from fogging. Just don't breathe on them!

 

[Ganderite]

When I worked at the CIL ammo division R & D lab, one of the test we did was to cold soak ammo at -40 for 3 days and then test it. The result was a very substantial loss of performance. Would a magnum primer improve results? It might. Would not hurt.

The second issue is ignition. Does the ammo go bang? As H4831 has said, any oil or grease in the bolt, spring, firing pin will be very stiff at low temp and reduce firing pin energy. Rinsing the bolt in kerosene and shooting dry is an excellent approach.

Some powders (ball) are harder to ignite. So are slow powders with lots of deterrent coating. The previous suggestion of using a magnum primer for all ball and any powder charge over 55 gr is a sound idea.

 

[klink1983]

Boomer, you are in an excellent area to do some hands on testing.
This winter, why don't you do some testing for us. Load exactly the same for two or three calibres, except in half use standard primers and in the other half use magnums. Treat them all exactly the same, having them out in the cold for some time before you shoot them over a chronograph, even alternating them shot for shot, as the rifles heat up.
I'm sure a lot of us would like to see the results.

Yes please!!

 

[klink1983]

When I worked at the CIL ammo division R & D lab, one of the test we did was to cold soak ammo at -40 for 3 days and then test it. The result was a very substantial loss of performance. Would a magnum primer improve results? It might. Would not hurt.

The second issue is ignition. Does the ammo go bang? As H4831 has said, any oil or grease in the bolt, spring, firing pin will be very stiff at low temp and reduce firing pin energy. Rinsing the bolt in kerosene and shooting dry is an excellent approach.

Some powders (ball) are harder to ignite. So are slow powders with lots of deterrent coating. The previous suggestion of using a magnum primer for all ball and any powder charge over 55 gr is a sound idea.

So what you are saying is that over the winter I should have my powder and primers stored in the house? That was my plan anyways but this helps me to convince my Wife that some reloading related activities will be going on in her quilting room over the winter. Her work bench is just as solid as mind...if not even more than mine.

 

[Ganderite]

So what you are saying is that over the winter I should have my powder and primers stored in the house? That was my plan anyways but this helps me to convince my Wife that some reloading related activities will be going on in her quilting room over the winter. Her work bench is just as solid as mind...if not even more than mine.

If you want to use me to explain why you and your ammo should be toasty while loading - go for it.

Bu the purpose of the cold soak was to see what would happen to ammo when used (hunting) in cold weather.

 

[Boomer]

Yes please!!

Over the next week I hope to select the cases and bullets for the test, Keeping tolerances as close as possible, load the ammo, and perhaps even do some warm weather shooting (although we've been hovering around zero) to provide an index of comparison. Then we'll have to wait until we get into the deep freeze to shoot the cold weather segment of the test.

 

[Dogleg]

Read Bruce's post. He's right on the money.

Failure to fire when cold is most often attributed to a gummy firing pin, not the primer.

How about we wait for Boomer 's test.

How about I tell you a story while we're waiting? Boomer won't mind.

I was developing loads for my first .338 Edge in the winter and was absolutely plagued with misfires. The primers on the misfires actually lit and welded 92 grains of H1000 into a solidified yellow mess that I had to scratch out of the cases with a nail but not enough to set it on fire. In 40 below weather only half were firing. 20 was better but still bad.
I know about as much about tearing down, lubing and cleaning bolts as anyone does, and since that particular rifle was a Savage could adjust the firing pin protrusion and free-play as well. No luck. Next I changed the striker spring to a 36 pound after-market post pounder, that didn't improve the reliability rate at all. Next was to dip into what was then a carefully guarded stash of Federal 215 Matches and I was rewarded by a endless string of loud bangs with no other changes.

The 215 was designed when the .378 Weatherby factory loads weren't reliably firing in the cold, not for some perceived sales benefit. Guys with expensive rifles shooting expensive factory ammo at dangerous game on expensive hunts tend to get all pissy when they don't work. Did you know that Federal also has a hotter 216 primer that isn't sold as a component? It was designed specifically for their line of Nitro Express ammo. Turns out guys with rifles that cost more than my first home, shooting ammo that per box rivals the price of my first car come completely unhinged when the ammo their double rifle is regulated for goes click.

 

[BigUglyMan]

I've always used magnum primers in my hunting rifles because I often hunt at -30C to -40C. Do I really need them? I don't really know but they put my mind at ease so what's the harm?

 

[kamlooky]

Hay Boomer, stick the ammo in the freezer and give them a head start.
Take a cooler with ice to keep them frosty.
This has my nose twitch'n.

 

[blackbeard]

will accuracy change going from large rifle to large rifle mag primers?

 

[Ganderite]

Changing to a mag primer is a change in the load, so the grouping might change one way or the other, If I was changing to a mag primer, i would drop the powder charge a grain and then try that and two more increments to see what was best.