Using magnum large rifle primers in .308 Win?

[rdelliott]

Just got back from Higginson Powders, where I picked up a Lee turret kit and some other reloading supplies. Having recently bought a Norc M-14, I've decided to start reloading

I got everything I needed, but Higginson was out of regular large rifle primers, and so I picked up some Winchester magnum rifle primers instead.

Yes, I know that with an M-14, it's advisable to seat the primers deeply.

If I understand correctly, using magnum primers will generate higher chamber pressures, and so I should load less powder to compensate for this.

I'm going to be using Winchester brass, H4895, and 150 grain bulk FMJ. Any suggestions as to how much I should underload by? Any tips and suggestions for a complete n00b?

 

[thebaron]

Reduce your powder load by 1 grain. I load the same powder in my 30-06 with large magnums... Shoots great.

 

[Boomer454]

Safest way is to start with the minimum as listed in your manual, just like you would with the standard primers. Usually when you change any component you should start at the minimum load and work up again.

If it is a tried and true load then by all means just reduce the load one grain. But watch for pressure signs!

 

[H4831]

Primers

I have never noticed the slightest difference in pressure by using different primers, magnum or otherwise.
Several years ago in a Reloaders Digest, I think it was, was a well researched article on primers. They tested thousands of loads, using every type primer on the market. The bottom line was the firing pin hitting the primer, hard, medium or soft, had more effect on the burning rate and pressure of the primer, than did the primer itself.
In other words, a magnum primer fired by a weak hit by the firing pin had less heat, pressure, whatever, than did a standard primer hit by a heavy firing pin.
The same held true for the various brands of primers.

 

[mbogo3]

I use magnum primers for everything except cast loads.Recommended for sub-zero hunting conditions and all ball powders.............Harold

 

[Skullboy]

I use magnum primers for everything except cast loads.Recommended for sub-zero hunting conditions and all ball powders.............Harold

Bingo!!!!............I use Magnum primers for my hunting loads where it get REALLY cold, and have used them when using ball powders.

Magnum primers burn hotter and ignite the powder the the instances mentioned above.

Drop down a grain or two and work your load up.............

I noticed a slight gain in velocity, but nothing to write home about.Accuracy was the same........

SKBY.

 

[savagefan]

The copper is thicker on a mag primer also.

 

[Norm99]

Don't mean to hijack the thread, but just a quick question related to this. I'm loading wsm for the first time and the loads call for magnum primers. I only have large rifle primers on hand. Is it necessary to go out and buy magnum primers or can I just use the large rifle primers that I already have? I notice one manual says to use either WLR or Magnum, but the other that I have says to use Magnum. Thanks.

 

[Boomer]

My rule of thumb was to use a magnum primer in cold temperatures or when the powder charge exceeded 50 grs. Some folks think they are a good idea with all ball powder loads as well. Since I've lived the north, I use magnum primers for almost everything, and like H4831 says, I don't see any significant difference.