Standard primers for .257 Weatherby Mag.

NVDesertHunter

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Sep 8, 2016
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Hello all,

I am starting to reload for my .257 Wby. Mag. and have given up the search for magnum primers. However, I have 100's of Winchester Large Rifle primers that I use for my .280AI.

My question is: would my WLR primers be sufficient for my .257 Wby.?

according to this "garage study", it seems that Winchester LR primers are almost as powerful as other magnum primers:

is there another study online that tested primer "hottest"? or has anyone had experience using WLR primers for their .257Wby.?

thanks,
 
Never used the WLR in any of my Weatherby rifles. I’ve also never seen load data use anything but a magnum primer more specifically the Fed 215m.
 
Might work. Might give you great accuracy in your testing. Might be very reliable from the bench or at the range during the mild or hot weather. People shoot 308 with SRPs in summer matches all of the time.

Now, let the temperature drop below freezing and the animal that you’ve been seeking be in your sights and it may not ignite properly when you touch the trigger. There is a reason that magnum primers were developed and spec’d. I’m not willing to take that chance.
 
I'd imagine it would work but as mentioned earlier in the severe cold weird things could happen. You might be able to test that theory if you get creative.
 
My under standing about primer's is that Magnum primer's purpose is to ignite large case's of slow burning powder and ball powder which is supposed to be harder to ignite. I use standard primers with H335 and H414, both ball powders. Don't shoot any magnums anymore but when I did I always used mag primer's because the book said to! never did even try standard primer's but that was long ago. Today I believe I would try them. Not sure what the worst that could happen might be. But here's the thing, I'm not trying them nor is anyone else here. You are! If I felt the need to question it, I simply would not do it. Start dealing with pressure and the only opinion that matter's to me is mine! If I knew more about it I could be an engineer for some ammo company or rifle company.
 
I thought "mag" primers were developed for the huge cases that hold 80-90+ grains powder. A 257 Weatherby case really isn't that much bigger case than say a 280rem AI. 60gr of powder vs what 65-70gr?

I'd do it if that's all I had. Good luck, if you lived nearby I'd swap some with you.
 
I thought "mag" primers were developed for the huge cases that hold 80-90+ grains powder. A 257 Weatherby case really isn't that much bigger case than say a 280rem AI. 60gr of powder vs what 65-70gr?

I'd do it if that's all I had. Good luck, if you lived nearby I'd swap some with you.
For some reason I recall reading somewhere the Fed 215 m primer was developed for the Weatherby cartridges. I want to say it was in the Roy Weatherby book. I could be incorrect on this thought.
 
For some reason I recall reading somewhere the Fed 215 m primer was developed for the Weatherby cartridges. I want to say it was in the Roy Weatherby book. I could be incorrect on this thought.
You could be right, but it was likely for the 378 and 460 class cartridge's that hold 115gr of powder. Big difference between them and a 257.
 
You could be right, but it was likely for the 378 and 460 class cartridge's that hold 115gr of powder. Big difference between them and a 257.
Weren’t the bigger weatherbys developed later after the 300,257,etc?
 
I thought "mag" primers were developed for the huge cases that hold 80-90+ grains powder. A 257 Weatherby case really isn't that much bigger case than say a 280rem AI. 60gr of powder vs what 65-70gr?

I'd do it if that's all I had. Good luck, if you lived nearby I'd swap some with you.
The 257wby parent case is the 300 H&H. The 257 case capacity for water is anywhere from 81.2-84.8gr. The 280 ai can hold anywhere from 60.1-68gr. Those the published numbers from nosler.
 
Weren’t the bigger weatherbys developed later after the 300,257,etc?
Not sure on timeline, but the Rigby has been around a lot longer than all of them, and IIRC it was the basis for the 378 Weatherby and then he add a belt. What I remember reading somewhere was that mag primers haven't been around as long as "magnum" cases. I wouldn't be scared to use a LR in a 257 if that's all I had. What would happen? Maybe a hang fire... maybe if its really cold and you're using really slow burning ball powder or something.
 
Hello all,

I am starting to reload for my .257 Wby. Mag. and have given up the search for magnum primers. However, I have 100's of Winchester Large Rifle primers that I use for my .280AI.

My question is: would my WLR primers be sufficient for my .257 Wby.?

according to this "garage study", it seems that Winchester LR primers are almost as powerful as other magnum primers:

is there another study online that tested primer "hottest"? or has anyone had experience using WLR primers for their .257Wby.?

thanks,
Where are you located? If you were near me I’d gladly hook you up with some magnums, maybe someone else near you would do the same.
 
Thanks all for the feedback.

I most likely will be reloading 100gn Barnes TTSX with IMR4350, which certainly isn't the slowest burning powder out there and the large rifle primers have no problem igniting 55.2 gn of it in my other rifle.

I'm in Reno NV so if anyone is nearby or swings through, shoot me a message and I would be happy to trade a few LR for LRM primers.

cheers,
Russell
 
Thanks all for the feedback.

I most likely will be reloading 100gn Barnes TTSX with IMR4350, which certainly isn't the slowest burning powder out there and the large rifle primers have no problem igniting 55.2 gn of it in my other rifle.

I'm in Reno NV so if anyone is nearby or swings through, shoot me a message and I would be happy to trade a few LR for LRM primers.

cheers,
Russell
I'm in Carson City, I'd be happy to help you out.
 
Once you reach or exceed around 60gr. of powder in any rifle cartridge, a magnum primers is an extra good idea.
 
Saw Natchez had Fed Mag LR primers earlier today. Seems like all the dealers get stuff in waves, so I’d keep an eye out here in the next few days and you might get lucky!
 
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