What primer for 300 mag?

[oldhammy1]

I am looking at loading 165 grain nosler balistic tips for my new 300 win mag. I plan on using IMR 4350, a couple of grains short of max, and working my way up. The only thing I do not have a feel for is if I need to use large rifle magnum primers, or if the large rifle primers are sufficient. Does anyone have experience with this, or can provide a recommendation?

Thanks.

 

[Mal H]

You should definitely use a magnum primer with both the 300 Winchester magnum and 300 Weatherby Magnum. There's a lot of powder in those cases and a magnum primer is essential for good ignition - that goes for all powders recommended for those calibers.

Don't your reloading manuals make a primer recommendation?

 

[JackOfAllTradesMasterAtNone]

I did some testing years ago...

Benchrest primers, magnum primers and standard LRP's with .300 Weatherby, .300WM, .338WM and my 30-338. Although I didn't see as much variation in muzzle velocities with the shorter cases, extreme deviation was noticable with standard primers touching off 4064, RL22 and 4350 for the larger capacity cartridges. Accuracy didn't seem to suffer much from the sporting rifles I was shooting. Only two of them were capable of 1moa anyway. Still, having read your other threads about long range shooting, I'll pass on my experiences saying that you don't need to run the same tests. Don't waste your time using standard primers with the large capacity cartridges. They'll all go boom for sure, but like Mal said, "There's a lot of powder in those cases".

-Steve

 

[oldhammy1]

Thanks. I did read the manual, and planned on using magnums, but several have posted that there are some advantages to using large rifle primers. I think they are referring more to short mags. Anyway, I appreciate the info. I currently use CCI 200's for my 0-6 and 270, and plan on using CCI 250's for the 300.