Magnum Primer for Cold weather...non-MAG cartridges.

350 Mag

350 Mag

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Is there any truth to Magnum primers being better for cold weather for temp sensitive powders.....been reading some info about guys using MP in non-mag cartridges for cold weather loads.

Yes I know there is some loading manuals that reccomend MP for certain powders in nonMag cases.
 
My 6slr likes h1000 but in cold weather I was loosing almost 200 fps so for me magnum primers was the ticket.
I also used MP in my 220 swift with h380 but that was denoted in my loading manual .
It seems that MP will help cold weather from what I have tested at least in my slr.
 
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Boomer said:
You can decide for yourself . . .
http://www.canadiangunnutz.com/forum/showthread.php/1042057-Cold-Weather-Primer-Test
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Interesting results...

I will stick with my method......develope your loads as close to the ambient temps you will be using them in the field, thats why I do majority of my load developement in Spring and Fall.


It would intersting to see POI shift on target with ammo that is warm and ammo that is frozen....lot of variables that would be almost immposible to deal with in real world hunting situations?
 
Good to know. I bought 300 large rifle magnum primers when primers were scarce and didn't really shoot in the cold. Might use 'em for plinking with lighter loads to be safe, no?
 
350 Mag said:
Interesting results...

I will stick with my method......develope your loads as close to the ambient temps you will be using them in the field, thats why I do majority of my load developement in Spring and Fall.


It would intersting to see POI shift on target with ammo that is warm and ammo that is frozen....lot of variables that would be almost immposible to deal with in real world hunting situations?
Click to expand...

The cartridges I've used most in the cold are my .30/06 and .375 Ultra, and between warm and cold temperatures there seems to be about a 4 MOA difference in trajectory with loads that nominally produce 3000 fps. However there is more going on to affect the trajectory between the muzzle and a distant target than can be explained by ignition issues which may effect the chamber pressure developed by a given powder, that in turn can be controlled by increasing primer brisance in low temperatures, and is best measured by muzzle velocity. As air temperature decreases, air density increases, thereby effectively reducing the BC of your bullet. Another issue is that when one is all dressed up for the cold, your eye does not look through the scope or across the sights the same as when its warm, because your bulky clothing and head gear changes the LOP and your cheek weld. This might have more to do with a dramatic change in POI, between summer and winter, than can be explained by changes in internal ballistics.
 
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If it drops below 0'C, non-magnum primers will have a 100% failure rate. It's physically/chemically impossible for them to ignite any powder below freezing. I read it here on CGN so it has to be true :jerkit:
I guess that would mean there was no fighting in WW2 in the winter as magnum primers hadn't been invented yet?

I have been switching over everything to magnum personally just because they seem easier to find. Regular primers are sold out far more often than magnums. PoI change has been less than 1 MoA in all my rifles so far.
 
LUTNIT said:
If it drops below 0'C, non-magnum primers will have a 100% failure rate. It's physically/chemically impossible for them to ignite any powder below freezing. I read it here on CGN so it has to be true :jerkit:
I guess that would mean there was no fighting in WW2 in the winter as magnum primers hadn't been invented yet?

I have been switching over everything to magnum personally just because they seem easier to find. Regular primers are sold out far more often than magnums. PoI change has been less than 1 MoA in all my rifles so far.
Click to expand...


What is the temperature range you normally shoot in?
 
When I was at CIL we tested ammo by leaving it in a freezer at -40 for 3 days, then shooting it. We had small cooler chests to carry it from the freezer (upstairs) to the range (downstairs). Velocity drop was dramatic. We were just pleased to see it go Bang.

Magnum primer for cold wx is a good idea. But make sure the bolt has been washed dry of lubricants.
 
The cartridge name has absolutely nothing to do with magnum primers. They're about the powder(s) used. They burn a bit hotter for a bit longer and are used to light hard to ignite powders. ('A bit' being measured in nanoseconds and nanodegrees. Made the latter one up.) However, cold weather is the other reason for using magnum primers. Some powders really dislike the cold.
If you change any one component you really should work the load up again
 
350 Mag said:
Interesting results...

I will stick with my method......develope your loads as close to the ambient temps you will be using them in the field, thats why I do majority of my load developement in Spring and Fall.


It would intersting to see POI shift on target with ammo that is warm and ammo that is frozen....lot of variables that would be almost immposible to deal with in real world hunting situations?
Click to expand...

Mostly I'm replying here so that sunray doesn't have the last word.;)

I dislike having to spend time at the loading bench immediately before going shooting, which tends to be a spur of the moment thing, so when I load, I never know how far into the future, or at what time of year the ammo might be used. Based on the load data, I know what sight correction must be made for temperature, thus my loads and primers don't change for season once I've got the load worked up. My working loads are usually about a full grain below maximum for my individual rifle, so I don't get sticky extraction in the heat, or unreasonably low velocity in the cold.
 
One thing to remember is that in some places you can hunt right through from mid-August until the end of April. Temperatures you might hunt in range anywhere from +15 to -45C. Too much temperature change. I've used magnum primers in the 30-06, 25-06 and 9.3x62 for years. But if you only hunt for a month or so through the year and in a set range of temperatures then you're probably fine. Except that you're a poor sap who lives somewhere with crappy hunting seasons. I'm not being hateful, I'm the same kind of poor sap now.
 
The powder you put in the case is the gasoline you put in your car.

The primer is the spark plug in your cars engine.

If you look in a Speer manual they tell you what spark plug to use.

The American military uses magnum type primers in all their ammunition.

And when Remington ran our Lake City Army Ammunition Plant the 7 1/2 primer was used in all 5.56 ammunition. The 7 1/2 primer was used to light off the harder to ignite Winchester double base ball powders loaded at Lake City.


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4WinchesterWSR_zpse39fa6ea.jpg


3CCIBR4_zpsa43a3c3a.jpg
 
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I lifted this from Accurate reloading. They aren't trying to claim to be scientific, but they did try a lot of different primers on some different cartridges, then froze the ammo and did it again. Results are mixed, velocities changed by varying amounts and something that I found notable is the accuracy almost always dropped. Its interesting if nothing else.

http://www.accuratereloading.com/primer.html
 
Dogleg said:
I lifted this from Accurate reloading. They aren't trying to claim to be scientific, but they did try a lot of different primers on some different cartridges, then froze the ammo and did it again. Results are mixed, velocities changed by varying amounts and something that I found notable is the accuracy almost always dropped. Its interesting if nothing else.

http://www.accuratereloading.com/primer.html
Click to expand...

I was disappointed they didn't mention what the actual temperature of the ammo was, but I assume it was probably cold enough to keep the ice cream from running out on the floor, but may or may not have been what we consider cold. Whatever the temperature was, the differences in velocity and accuracy were measurable. One advantage of the freezer method is that there was no issue with ice crystal glints confusing the photo cells of the chronograph, which when combined with the small sample size I used, and when combined with the .270's velocity hiccup (probably the result of a work hardened neck as I was more concerned with identical case volume, than I was the number of times each cartridge case had been fired) would probably be enough for anyone used to testing under controlled conditions to dismiss my findings. In hindsight I should have annealed my case necks, but that opens up another can of worms with respect to uniformity, and precision annealing with respect to temperature and annealed width, is beyond my capability. There was little I could have done about the ice crystals. Another advantage they had was they could add the accuracy component which would have been irrelevant in my test due to the strong wind and bulky clothing which interferes with LOP and cheek weld. Saeed's cold temperature disadvantage was maintaining the temperature of the rifles, and they don't say of there was any attempt to do so.

Dogleg, thanks for posting this, it saves me from going through this again, comparing magnum and standard primers this summer.
 
Boomer said:
What is the temperature range you normally shoot in?
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Normally +30'C to -10'C
On occasion +35'C to -25'C
(excluding humidex or wind chill)

I've shot down to -25'C with no FTF's or hang fires with non-mag primers. Always used CCI exclusively until less than a year ago when I started having a hard time finding them and switched a lot of my loads over to Winchester magnum primers. I haven't chronied anything below around 0'C though. I would assume there would be velocity drops.
I had one hang fire by about half a second recently. Was around 0'C in a Savage 223 using CCI small magnum primers. No idea what caused it and it's my first malfunction of any kind with CCI primers (a little less than 10k CCI primers used personally).
No issues with Winchester primers yet but I've barely broken 2000.
I do get vertical PoI changes with temperature but under similar conditions, switching from regular to magnum primers almost always results in a 1 MoA shift to the left for some reason.
 
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