Milspec primers for AR's not necessary?? See what the manufacturers have to say.

Most people think that the CCI #41 is the only safe primer for fire arms with free floating firing pins such as the AR-15. I contacted several manufacturers to see what they had to say on the subject and if their primers were ok with these types of firearms.

CCI:
Hello,
Could you please tell me what the difference is between the CCI 400 primer and the CCI 41 primer? Does the 41 primer have a thicker/harder cup and less sensitive priming compound then the 400 primer?

Response:
A CCI 400 is our 'standard strength' of small rifle primer.

A CCI #41 primer is a 'magnum' strength of primer, equivalent to our CCI 450 Small Magnum rifle primer, ballistically. The #41 primer also has a feature to help lessen the chance of a slam fire in semi-auto types of firearms. This feature is that there is more distance between the tip of the anvil and the bottom of the cup, creating a slightly less sensitive primer. The #41 primer also has a thicker bottom on the cup than the CCI 400 primer.

Linda Olin
CCI/Speer Technical Services
2299 Snake River Ave.
Lewiston, ID 83501

Remington:
Said their 7 ½ primer is what is used in their ammunition and is safe for firearms with free floating firing pins.

Winchester:
Said their WRS primer was safe for firearms with free floating firing pins and would not cause a slamfire. However they use different primers in ammunition that is for their military contracts.

Federal:
Said that 200 and 205M was not meant for firearms with free floating firing pins but they just came out with a primer for AR’s called the GM205MAR (Gold Medal 205 Magnum AR)


Primer cup thickness:

CCI 400 - 0.020
CCI 41 - 0.025
CCI 450 - 0.025
CCI BR4 - 0.025
Rem 7 ½ - 0.025
Win WSR - 0.021
Fed 200 - 0.019
Fed 250 – 0.0225
Fed GM205MAR – N/A

I personally think that manufacturers play the milspec primers up a bit. For example if AR’s were only safe to shoot with milspec primers how come Remington doesn’t have one, Winchester says their WSR is safe, and what did Federal do before the GM205MAR?? I would think their ammo would have had some disclaimer saying it was not safe for firearms with free floating firing pins. Also if you notice the WSR and CCI 400 have thin cups and according to Winchester the WSR is safe. Also notice how the CCI 450 and BR4 have the same cup thickness as the 41. If using the #41 makes you feel better about your reloads then go for it. I feel that it is not necessary and according to the manufacturers not the only option.

It may be true but I'm not changing over. I like the 41's

When I first started I used the WSR, not knowing that it "required" a milspec primer. I had no problems. Then I switched to the Federal which is supposed to be the most sensitive of the group, still no problems. I then tried some CCI #41, and had 3 out of 10 fail to fire with my Timney Trigger.

I've gone back to the Federals. I uniform all my primer pockets and make sure my primers are seated to the correct depth. I also make sure my firing pin in clean. I have not had a problem yet, but I know there are others that have.

I've always wondered the same thing, if CCI #41 are the only ones that are "OK" what has Remington, Winchester, etc done for their factory ammo.

Take it with a grain of salt.

I nominate this to be a sticky. That is reference material.

I have used nothing but WSR's and CCI400's in my 223's and never had any issues with thousands of rounds.

If all AR's were chambered for 556 nato...maybe. But half are 223 Rem and the rest are other calibers that never used mil-spec anything....like the 204 ruger for example.

Keep your weapon clean and keep shooting

From what I understand it's only a problem with the full auto guns with high cyclic rates. In semi auto you can use purdy much any primer you want.