Large rifle primers vs. Large rifle magnum primers in .300 win. Mag.

[Shoottothrill]

Just curious as to others experiences between magnum and non-magnum primers in the the .300 win mag shooting the heavier bullets 215gr. to 230gr. Going to be using H1000, and Winchester brass. Appreciate any primer recommendations as well. Looking to put together a long range accurate load.

1. Does one produce lower ES and SD numbers than the other?

2. Does one produce better accuracy.

3. Does a Magnum primer produce any velocity benefits?

 

[FCS]

1) Yes, but you'll have to test each to find out which is which in your rifle.

2) Yes, but you'll have to test each to find out which is better in your rifle.

3) Yes, usually a magnum rifle primer is worth about 25-30 fps but again, really depends on your rifle.

Generally speaking I've gotten better performance with GM210M than GM215M in 300 WM with the powder and bullets you mention. Sometimes the GM215M works better. Your rifle will tell you what it likes best. BR2s have worked quite well.


Custom barrel / chamber or a factory bbl / chamber?

 

[Ryguy]

Just today I had hang fires with Sellier and Bellot Large rifle magnum primers. I can imagine, with the right powder combination a regular large rifle primer could do the same thing. 215GM primers do me very well. Retumbo gave me the best velocity with the 210 Berger and 208 Amax while Norma 217 gave me the same accuracy but with less velocity and more manageable recoil, and hoping barrel life.

 

[Shoottothrill]

1) Yes, but you'll have to test each to find out which is which in your rifle.

2) Yes, but you'll have to test each to find out which is better in your rifle.

3) Yes, usually a magnum rifle primer is worth about 25-30 fps but again, really depends on your rifle.

Generally speaking I've gotten better performance with GM210M than GM215M in 300 WM with the powder and bullets you mention. Sometimes the GM215M works better. Your rifle will tell you what it likes best. BR2s have worked quite well.


Custom barrel / chamber or a factory bbl / chamber?

My .300 is being built by S.A.C, It will have their Alpha 11 action, chambered for the 215 berger hybrid and 230 gr heavies, it has a Bartlein 28" MTU Barrel.

Thanks for any advice.

 

[FCS]

I'd start with GM210M or BR2s, I've used both in 300WM ammo with components you are going to be using. Never had an issue with a hang fire but I've only used in temps down to 20 F, maybe mid teens.

IF you just can't get accuracy or desired ES / SD numbers then you might need to try GM215Ms or CCI 250s.

I'm not trying to be elusive, just that your rifle is going to be final judge on the LR / LRM primer question. None of us can give you an absolute answer on primer to use in your rifle. I can say that on a very similar build with very similar components that GM210M / BR2 performed better for me than did GM215M.

 

[ArmyJerry]

I use wolf LR primers.

 

[Aimsmall55]

Brian Litz told me that he recommended using LR primers in the Win Mag as they will almost certainly drop your ES. If I'd listen to anyone it would be him

 

[Huckleberry75]

Brian Litz told me that he recommended using LR primers in the Win Mag as they will almost certainly drop your ES. If I'd listen to anyone it would be him

I have seen Brian post this exact same advice here before.