Standard or Magnum primers in the AR

SDCoyoteCaller

SDCoyoteCaller

Active member
OK guys, I finally broke down and got my first AR in .223, and now I am eager to start working up a load for it. My queastion is: Is it best to use standard or magnum small rifle primers in the AR?

I ran a search, but didn't really find what I was looking for. Thanks a bunch.
 
I've used both in my ARs with no problem and I use mostly fine ball powders...If you set aside accuracy quests, the main concern about using a standard primer in an AR, or other semi-autos with 'free floating' firing pins is the potential (not probability) for a "slam fire" when dropping the bolt carrier group on a live cartridge....

In all of my shooting with an AR, I've only personally known of it happening one time and that was at the DPMS 3-gun match in St Cloud MN in 2006 and it happened to a friend of mine...It disqualified him and he lost about $1,000 (entry fee, travel, etc) due to the Accidental Discharge rule..

Is it a major concern??? not in most cases, but it can be a problem in some instances..When you release the BCG to chamber a live round, extract the round and look at the primer.. It's' not unusual to see a very small dent where the firing pin has struck it...just not hard enough to ignite the primer...

The difference between the standard and magnum primers is the thickness of the primer cup and therein lies the potential danger...

I do, however, seem to get better accuracy using the magnum primers in my AR ammunition that I reload..
 
I use standard Bench rest primers exclusivly.. I tried a few loads with CCI magnium primers, but accuracy went out the window.. FWIW the Bench primers are thicker than regular primers. Somewhere on this forum there is a link to primer construction and diminsions for all the various manufacterers....
 
Primerspecs.jpg
 
i used magnums end of '08 beginning of'09 when you couldn't find any, had no probs, unless your working something custom i would stick w/ the hand book recipe.....
 
Thanks alot fellas. The chart is great. I currently have Winchester small rifle primers and they look like they have a slightly thicker cup than the other standard primers, so I think I will give them a try. I am glad to hear that the likelihood of getting a slam fire with standard primers is pretty low.

On a side note, I noticed from the chart that the cup thickness for large rifle primers are all the same. Is there a reason for such variability with small rifle primers? Just curious. Thanks for the help.
 
I have used both. I used the magnum primer with h335, and h380. I have used mostly federal small rifle primers. I have had no problems with any/either. Good luck and happy shooting.
 
Ditto what Lurker and Turtle mention.

I use either 3031 with reg primers and X-term with Magnum primers.

If you PM him, RustyDitchRider had worked up some magical loads for his 1 in 9 barreled AR with X-term and mag primers that were, IIRC, less than a quarter of an inch.

My accuracy is hovering around .6 to .8 of an inch.

Happy loading!
 
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