How much to reduce powder charge when changing primers?

[txsendero]

I'm shooting 7mm Rem Mag, WW brass, 71.9 gr Retumbo under 168 gr Berger VLD with Fed 215magnum primers. How much should I reduce the powder charge before working back up if I want to try WLRM primers? 1 grain? 2 grains? I am trying to find out if the change in primer may give me better ES.
Thanks

 

[boomtube]

Are your present loads on the ragged edge of blowing your rifle apart?

If not, you really don't NEED to reduce the charge at all.

Or, you could just reduce by 3.4 grains and see what happens. ??

 

[johnnyk]

I usually treat it like a totally different load. I start at the minimum and work up to max. JohnnyK.

 

[royinidaho]

I just change primers and let'er rip. However, you may wish to consider differently when going from standard to magnum.