Magnum primers,

[dirtykid]

It has probably been covered before on here,
But all I could find recently on a shelf was Magnum primers for my rifle,
I had worked up a nice load for my .243 with 65gr Vmax/4895/CCI200 ,
I wanted to try to stretch the konockdown with a 75gr pill,

All that was available was CCI 250's so I started on the lower-end of the scale for the 75gr (range of 31.4 to 38gr max) at a comfortable 32gr of 4895

Now I read in a few forums that the STARTING load should be about 10% BELOW the lowest load ??

What say you of THR ?
Does a Magnum primer really add that much initial pressure spike ?

 

[rcmodel]

STARTING load should be about 10% BELOW the lowest load ??

Totally wrong.

The Starting load should never be reduced any further then the load data calls for.
And that is usually a 10% reduction from the MAX load.

Changing components like primers, cases, and to some extent bullets without running into unexpected pressure problems is why it is called a Starting load.

rc

 

[NCsmitty]

You will be fine using the starting loads listed, the problem may occur when using a maximum listed charge with standard primers, and then substituting magnum primers. I find backing off 5% of a previous load using standard primers is the sensible caution when substituting magnum primers.


NCsmitty

 

[dirtykid]

Thanks Rc,

Now when the temps get close to freezing, and we dont have wind gusts up to 30mph,
I can comfortably place my melon inches away from the action without fear of
a unexpected detonation in the chamber,

 

[dirtykid]

Thanks to both of you guys,

I guess thats what I get for reading too much on the internet,
too much mis-information often gets parroted among the various forums,
and there often is not someone that will chime-in with the BS-flag ..