Magnum primers as opposed to normal large primers

[ryaninutah]

I'm pretty new at reloading and have been loading my 300 WSM with normal large primers, as opposed to magnum primers. Will I really see a performance difference with magnum primers, and should I make the switch?

Thanks everyone

 

[80Maro]

Your reloading manuel should state which primer was used for testing for each cartridge. I would go by what that book says.

 

[ryaninutah]

Thanks. I looked at the book, and they did use magnum primers. But I was just wondering if anyone knows what the performance difference is.

Thanks again

 

[rscott5028]

You can try either one for accuracy as part of your load development.

To be safe, you should always back down and work up if changing components.

As a general rule of thumb, Mag primers are preferred for ball powders and loads greater than about 60 grains of powder to ensure good ignition in freezing weather.

-- richard

 

[BSF350]

Just my 2 cents from a also new to reloading. I was told to use Magnums Primers on 4350 and slower. There are 3 4350 but they are all in the same range. Slower powder may need a magnum primer.

 

[bbutturff]

I had this same conversation with a friend last June. He always uses CCI200s in his 300 RUM and I always use CCI250s in my 300 WSM. Just for grins we swapped a hundred. He claims his MV went up 150-200 fps and his ES went down simply by using the hotter 250s. I don't know what powder he uses in this load but it's safe to say it's one of the magnum powders. I haven't tried the 200s in any of my pet loads yet but I would expect to see a difference.

 

[rscott5028]

I had this same conversation with a friend last June. He always uses CCI200s in his 300 RUM and I always use CCI250s in my 300 WSM. Just for grins we swapped a hundred. He claims his MV went up 150-200 fps and his ES went down simply by using the hotter 250s. I don't know what powder he uses in this load but it's safe to say it's one of the magnum powders. I haven't tried the 200s in any of my pet loads yet but I would expect to see a difference.

No surprise there.
300 RUM uses more than 60 grains of powder for just about any reallistic load.

 

[djtjr]

Every gun is different I have used non mag primers all the way up to the 338 lapua and in most instances got better groups and es than with mags. See what your gun likes and work up when chaAnging components

 

[royinidaho]

Follow richards guidance. It's good!

My experience says that in '06 sized cases and most probably smaller, CCi 200s have always shown greater accuracy that cci 250s, in my rifles.

In large case magnums, I've found, as revealed by a noted rifle smith, that Federal 215s are a bit hotter than Federal 215 GMs.

Again follow the advice given.