Originally Posted by .280Rem
Need? Nope. In fact, some say Winchester Large Rifle Primers are about as hot as other Mag primers. My general rule of thumb is 60 or more grains of powder I use them, but you don't need them. There is a line of thought among some loaders that you do best to "light the powder" with as little fire as possible.
Well now Counselor the objective is to light the powder as efficiently as possible, ensure complete and consistent ignition every single time in all temperature conditions that will be encountered by the rifle when being fired. I do not know how much experience you have with H1000 but I can tell you that with years of lighting off too many pounds to remember, in many calibers from the 338 Lapua Improved wildcat to several different 7 mag variants I can assure you that H1000 benefits from the use of magnum primers.
In the development of loading data for mine as well as other folks I have worked with over the years the Winchester primer you speak of is on the hotter side. This I will agree with as not only my testing confirms but one of my good friends who I shoot in competition with works for one of the bullet manufactures and actually told me years ago about the Winchester primers being this way. Based on his recommendations my testing started with WLR primers on load development where ball or large amounts of propellant were required esp in the longer cases. In almost all cases the 215M has provided better accuracy, shot to shot deviations as well as velocities in the temperatures tested here (approx 40 to 95).
To make the general statement that magnum primers are not needed indicates that your personal experience in this discipline is not comprehensive or complete as it should be. This site is dedicated to the long range hunting and shooting art not short range. You may rest assured that velocity and more importantly at range, shot-to-shot vertical dispersion can mean the difference in success or failure in the field or in competition for that matter. To this end the slower burning and larger capacity cases typically used in this endeavor lend themselves very well to the use of magnum primers.