Primer choice: large rifle or magnum ?

gitrdun

gitrdun

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Currently, I am using the WLRM primer for my .270WSM. However, I recall seeing some load data (can't remember where) which uses a Large Rifle primer (not a magnum) for the .270WSM. So it seems to me that this cartridge can use either. The reason I ask is because I have 200 CCI BR2 benchrest primers that were intended for a 7mm-08 that I sold. Would I be able to use these BR2's in my .270WSM for a hunting load?
 
as far as i know, it's your POWDER that dictates whether you need a MAGNUM primer or not- ball powders like 748 for instance, and the heavy slow burners
 
I use a large mag primer for my 300WM and the loads only call for a large primer. But I keep 1gr from max when loading because of mag primer.
 
I try each and see which works better. I had a 300 wsm and with h4350 I used magnum CCI primers, I have also always had better results in 3 different 270's usinf magnum primers.
 
you're going to have to do a LOT MORE THAN THAT-the magnum primer has a hotter flame and provides a DIFFERENT PRESSURE - so subbing directly a magnum primer for a standard without changing the powder charge could end up in a SEVERE over-pressure condition- THIS IS COVERED IN DETAIL IN THE LYMAN MANUAL, in the reference section- using a pressure gun, they fired 10 shots with different primers and recorded the pressure- same powder charge- the MAGNUM provided an over pressure situation , as did a federal- the rest of the test i can't remember off the top of my head- bottom line was that EVERY TIME YOU CHANGE COMPONENTS, YOU HAVE TO RE-WORK YOUR LOAD
 
I work up 90% of my rifle loads using Fed GM215M (magnum) primers. They are one of the last things I'll try changing if a certain loading doesn't work out.
 
All I use is the BR-2 in all my loads. I have a 338 that would not shoot better than a 2 1/2 inch group...and I did everyting to it you could. Then I talked with an old timer who used to work for us. He has forgotten more about loading than I would ever learn. He held three world records up until his death for long range rifle.

He told me the BR-2 primers are a bench rest primer, as the letters BR indicate. They are hand selected at the factory for uniformity. ( flip 100 of them in a primer tray and look at the anvil heights.) He told me that they had a longer and hotter Briscence ( spark) than a standard primer and were not such a hot blast as a magnum primer...they burned longer so they tend to light all the powder more uniformly.

I tried it...and boy did that 338 ever start to turn out some good targets....

BR-2......all I ever use now. Worth the extra couple of dollars per 100 if you ask me.

Hope that helps.

Paul
 
If you are using the WLRM, you are using the hottest primer available to the reloader. Subbing the BR2 will most likely lower pressures somewhat, and may also change the accuracy somewhat, but you should not run into any pressure problems with that substitution. As already mentioned, going from a standard to a magnum primer without working up from below again can be a problem. Regards, Eagleye.
 
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