Q: I am puzzled by all the different kinds of primers available (when they’re available at all!) and have a few queries for you.
Do I need to use magnum primers in my .270 Winchester? Would using a benchrest primer improve accuracy?
A: All primers can be counted on to deliver reliable and consistent ignition for ordinary shooting and handloading, but the different grades of primers are intended for different needs.
Standard primers are suitable for the majority of rifle handloading needs. They work best with fast- and medium-burning powders.
Magnum primers are designed for heavy charges of slow-burning powders, where a more sustained jet of flame is required to provide full ignition.
Magnum primers give a hotter, longer-burning flame which provides more uniform ignition and more stable bullet velocities with slow-igniting propellants.
Benchrest primers are manufactured with the utmost selectivity for consistency in the composition and quantity of primer compound and metal cups.
The handloader working with ordinary cartridges for use in standard hunting rifles will probably not be able to see any difference between standard and benchrest primers, but the extra uniformity of the latter will be very apparent to the benchrest shooter or a person working up super-accurate loads for long-range shooting and varminting.