Magnum primers

longwinters · Jul 19, 2006

Since several of you are using magnum primers in standard calibers . . . when would you go with a magnum primer over the regular large rifle primer? I understand that some powders need the mag primers to do what they need to do even in smaller calibers like the 243. But say in the 270/280 etc... range none of my reloading books (that I have noticed) suggest the mag primers.

Long

rick smith · Jul 19, 2006

I normally use WLR or Fed 210M in 30/06 sized cases but will try mag primers if I use anything slower than the 4831s. In my 280AI I am using IMR-7828 and WLRM primers. In my 300WSM I get better results with WLRs. Don't remember using mag primers in any smaller cases even with ball powders. Primers are the last thing I change when trying to shrink a group.Rick.

Blaine · Jul 20, 2006

longwinters":2do9vo6o said:
when would you go with a magnum primer over the regular large rifle primer? I understand that some powders need the mag primers to do what they need to do even in smaller calibers like the 243. But say in the 270/280 etc... range none of my reloading books (that I have noticed) suggest the mag primers.Long

Whenever they work best!!! :wink: All I know is that the Fed 215 GM Match Magnum primer is a crucial part of the best load I've found for my Stevens 200 - 308 Win. This load has produced a "best 4 out of 5 shots" group of .092" @ 100 yards!!! (I've compared 4 other primers in the same load and they don't work as well.) I tried the mag primer on a whim and was blown away when I saw the group. I load light enough that even with a mag primer, I didn't reduce the powder charge any, it was exactly the same as the other "regular" primers. I would caution, though, that if you are charging at anywhere near max, be sure to reduce the charge by at least 10% and work back up.

Blaine

Waffen · Jul 21, 2006

You have it right. Mag primers are needed for certian types of powder even in smaller cartriges. It's generally not a good idea to just decide to try a mag primer. If you are at the top end of the scale with a standard primer and switch to a mag primer it can actually cause a significant pressure spike. In the area of 12k CUP pressure from the numbers I have seen. Not enough to blow a gun up, but certianly something to be avoided.

I would probably just try a different brand of primer than just swap to the mag primer for the hell of it. That being said, some slower burning powders just like mag primers. If they call for it, then go for it.

fredj338 · Jul 23, 2006

I have pretty much backed off using mag. primers for anything but the largest carts. holding more than 75gr of powder. Fed. 210M are used for just about everything from .260ai to 7mm Dakota even w/ slower powders like RL22 & IMR7828.

Powerstroke · Jul 27, 2006

longwinters,

This same question plauged me recently. I've always used CCI BR's in about everything I have, including my .280 Remington. That round has taken me longer than any round to find a good combo, but I managed.
The .300RUM I started playing with became the issue. The BR primers were causing a hang-fire issue, on pretty much every round. Advice from here, and i've switched to the Fed Mag primers which resolved the issue.
My beliefes are also with case capacity of powder. If there is a low capacity powder charge does a mag primer make sense??