This is a discussion on Magnum primers really necessary for ball powders? within the Ammunition forums, part of the M14 M1A Forum category; I've always heard magnum primers are needed for ball powders because they
are harder to ignite. Is this a hard rule, personal preference, dictated by ...
I've always heard magnum primers are needed for ball powders because they
are harder to ignite. Is this a hard rule, personal preference, dictated by climate,
or more to do with particular calibers?
I can see ball powder in .308 needing magnum primers just because of
the large amount of powder in a .308 case.
But what about the comparatively small .223? Majority of load data
I see use standard small rifle primers. This got me wondering about
always using magnums.
Are there certain ball powders that are so hard to light up they
must have a magnum primer?
Ball powders are usually more difficult to ignite. Winchester primers are designed for ball powders and standard force Federal primers are pretty hot but in 30-30 Winchester and 30-06 and ball powders I've had hangfires with CCI-200 primers. The primers just aren't hot enough. Both in 30-30 and 30-06 I had less than full cases with ball powders which can allow the powder to move away from the primer, compounding the problem. Speer recommends magnum primers also with slow extruded powders in large cases or long cases, such as H4831 in 270 Winchester.
Time has shown that ball powders and compressed loads, more often than not; work better with magnum primers.
BTW, assuming the information I found is correct (I have no reason to believe it isn't), what makes magnum primers different is the inclusion of small particles of aluminum that act as tiny little fireballs that get pushed deep into the charge and help ignition.
You should either follow the recipe and use a magnum primer when it's called for, or if you are developing your own loads; use what works most consistently for you.
Probably, it certainly won’t hurt to use magnum primers with ball powders. As said before mil spec primers are more “magnum” than standard, though in my velocity tests, the difference in velocities between mil spec primers and standard I did not see a clear indication that mil spec primers were all that different from standard.
M1 Garand BMR Receiver Douglas Barrel 1:10 twist
150 gr FMJBT 1966 Ball
14 Nov 2011 T= 74 ° F
Ave Vel = 2545
Std Dev = 20
ES = 68
Low = 2513
High = 2581
Ave Vel = 2599
Std Dev = 22
ES = 75
High = 2637
Low = 2562
N = 10
Very good group
I will say that given a combination of cold weather, ball powders, and weak ignition, you will experience hangfires or squibs. I have had that happen with ball powder and the 35 Whelen in cold weather, with standard primers, and have had that happen in a M586 with AA#9 (a ball powder) and cold weather. The problem with the M586 was that the mainspring was old. I took it to the range in 40ish weather and had hangfires, misfires with 12 grains AA#9 powder. This round, the bullet loaded in the throat and I had to use a screwdriver to knock it back into the case, so I could open the cylinder. You would think that the primer was well hit by the looks of it.
Later I replaced the old mainspring and shot it in slightly warmer weather, nary a problem.
So, I believe the energy of the firing mechanism is at least as important as the type of primer. If you plan to use ball powder in cold weather, like tundra cold, I would replace the M1a/M1 mainspring with an extra power mainspring, which would not hurt in cold weather regardless of powder, use magnum primers and keep all oils and gunk out of the firing pin channel.