I use Federal 210M primers to ignite 59.0 grains of powder in my .243 - 284 Winchester. The load shoots a 75 grain Hornady V-MAX bullet at 3,972 fps. Five-shot groups average 0.32". A week ago I shot a three-shot group at 300 yards that measured less than 0.50".
I haven't loaded for the 6mm/284, but my experience with other cartridges indicates that, unless you really need them in order to ignite very large charges, magnum primers give significantly poorer accuracy than regular non-magnum ones.
Posts: 5883 | Location: People's Republic of Maryland | Registered: 11 March 2001
My experience is that even with very, very slow burning ball powders (surplus WC-872 for example), standard force primers are adequate. I agree that they usually result in more consistant accuracy. I even use standard primers in 7mm STW with 98 grains of ball powder.
Posts: 13349 | Location: Henly, TX, USA | Registered: 04 April 2001