Primers: When to use magnum.

[Touch not Squeeze]

What drawbacks are there for using a magnum primer, in a lighter round?

 

[Guest]

I generally don't use mag primers unless I am working with fairly large charges of ball powder, like in my 8x57 where I am using over 50gr of AA2520, and in that same neighborhood with W748. I also use them in my 30-30, which is where I started using them. Almost all load manuals show using mag primers with the 30-30, because of the ball powder issue. Apparently these ball powders are harder to consistently ignite, so mag primers work better. I suspect the issue is density of powder, but maybe I am wrong. I use Federal 215's for my 270Wby, but that's more obvious. I use standard stuff for my 243, and will for extruded powders for my 8x57 (like when I get around to working with RL15 for that one).

 

[Richracer1]

The only round I use non-magnum rifle primers is my 300 Savage. Just didn't see the sense of using magnum primers for this little round. I use the mag primers for my 270WSM, 300RUM, and 338WM. I guess the decision to use magnums vs regular is up to the reloader. Some caliber definitely need the mag primers, such as the RUMs, the big WBYs and so on, due to that's a lot of powder to ignite. Just my opinion and we all know they do vary.

 

[Alaska]

When using Ball powder I use mag Primers.......or when it is a Magnum Large Rifle I use WLRM or Fed 215 Match.

All others get Large Rifle Primers like Fed 210 Match or CCI Br2.

My 308 Win likes the mildest primer.....RWS 5341 and Rem 9 1/2.


Excessive Pressure!

 

[Powerstroke]

I can personally tell you that a standard bench-rest primer won't light the .300RUM.... or at least turns it into a ( click....fizzz.... BANG ) Can you say flinch !

 

[REDGREEN]

I use WLRM primers in everything from 25 06 up. They give more consistant ignition, imo. I tried the standard primers, and the deviation across the chrony was quite a bit higher. I like a 10 to 15 fps shot to shot difference. :grin: The standards were in the 25 to 45 fps range. Accuracy is always sub minute at 200 and 300 yards.

 

[Val]

How about following the recipe in the load book? That's what I do and use mag primers when the load recipe call them out.

 

[47]

You may want to be careful. (First let me say I am no expert) If the recipe calls for a standard primer and you are loading @ max, I would assume going to a magnum primer might be dangerous. Although I doubt the difference between standard and mag primers aren't that much, that magnum primer might put you into an overmax pressure situation again assumeing you are loaded right to max with a recipe that call for a stanard primer. Again though this is just a hunch on my part. I do not know for sure.