to use magnum primers or not

[genecole]

I am working up a load for my 7mm STW using a 160grain Failsafe moly bullet, with 68-70 grains of Accurate XMR 3100. my question is this, should i use CCI large rifle or CCI large rifle magnum primers.
Thanks
Gene Cole III

 

[Varmint Hunter]

I have been shooting the 7STW for years and have only used Fed 215 magnum primers. The large quantities of slow burning powder typical for this big case call for magnum primers.

A check of your loading manual should confirm the recommendation of magnum primers in the 7STW.

VH

 

[panman]

Yep,over 60grs of powder and go to Mag primers.60 and over powder is a lot to ask of a std.primer to burn.Now saing that in these times ov sortages,use what you can get.you may not get the best from your rifle,but yo can still shoot and will be able to try new loads.As been stated before,primers can and will change your groups,so,try them out on paper before going hunting .pan.