AR15 Primers

[SunnySlopes]

I’ve just started reloading .223 Remington for my AR15, and I had someone tell me that there are primers that I should specifically use for .223 in an AR. I checked my load manuals, and they all call for Small Rifle Primers. He said if I wasn’t sure, then to use Small Rifle Magnum Primers because SRP would cause slamfires.

Similar discussion here:
http://smith-wessonforum.com/reloading/629515-primers.html

 

[JJFitch]

www.sksboards.com:

A "primer" on primers!

SMALL RIFLE (.223/5.56) PRIMERS?

The .223 Remington or 5.56mm NATO round is commonly found in semiautomatic rifles and also has special primer considerations using Small Rifle-size primers. Some recommendations follow:
Primers used for .223 Rem. loads should have heavy cups to resist perforation at the high pressures normal for this round. Military 5.56mm primers have a cup thickness of about 0.24", compared to .020" or so that was traditional for the standard small rifle primers. Federal 205, 205M, Remington 7 1/2 BR, Winchester WSR, and CCI BR4, 450, #41, and Wolf/Tula SRM (QQQSRM or KVВ-5,56M) primers have cups of about the same thickness as military primers, and are the best to use when reloading the .223.

The Remington 6 1/2 and 7 1/2 are essentially the same. The 7 1/2 cup metal is thicker so that the primer can stand up to higher pressures... cup thickness is 25 percent greater... BRIAN PEARCE (quoting Remington), Pg. 14, HANDLOADER, October 2006.
The Remington 7 1/2 BR primer was developed for the hot, high-pressure 4100 fps. .17 Remington round and also used in .223 loads. When Freedom Arms transitioned the .454 Casull case to use the small primer, they picked the Rem. 7 1/2 BR because it gave reliable ignition and easily withstood the 65,000 psi generated by the hot pistol round. It is highly recommended for .223 AR15-type loads.

CCI states: "The CCI 400 primer does have a thinner cup bottom than CCI 450, #41 or BR4 primers. The appropriate primer for an AR15 platform is the CCI #41 primer, which helps to prevent slamfires. With this primer there is more 'distance' between the tip of the anvil and the bottom of the cup." [as per: Linda Olin - CCI/Speer Technical Services]. Despite this, it seems that most AR15 reloaders have experienced no problems using the BR4 and 450 thicker cupped primers in rifles in good condition. The #41 gives the greatest safety margin however.

The experts at 6mmBR.com have this to say about AR15 primer choice:
For use in semi-automatics and AR15s, we advise that you stick to CCI and Remington primers. These brands have harder cups and are much less likely to pierce primers. Also, the AR15 has a free-floating firing pin that dents the primer on loading. This creates a risk of slam fires. So you want hard primer cups. The latest generation of Winchester primers, with brass-colored cups, should be avoided for AR15 use. The old silver Winchester primers worked fine, but the current WSRs are soft and can be pierced more easily than CCI or Rem primers. A poll of Highpower competitors (mostly shooting ARs) showed that Rem 7 1/2 primers are the most popular (33.23%), followed by CCIs (25.78%). The majority of CCI users favored the CCI BR4s, but both CCI 400s (small rifle standard) and CCI 450s (small rifle magnum) were also popular. Only 10.25% of Highpower shooters polled used Federal primers (either 205M or 205). At the time of the poll, many shooters reported using WSRs, but this was the older version with silver cups.

Wolf/Tula also makes two small rifle primers that are suitable for 5.56 loading. First is their Small Rifle Magnum SRM primer (not the Standard). They have this to say: "If you are loading for an AR15 or Military Style semi auto rifle, or are loading high pressure cartridges in any other type of rifle ,we recommend you use the Magnum Small rifle primers. Both primers use the same amount of compound. The only difference is in the cup hardness. The WOLF/TULA Standard Small Rifle Primers have an all COPPER CUP, which is a little more sensitive than the brass cup magnum primers." Second is their newer Wolf/Tula Small Rifle 223 SR223 "This is the newest primer available in the Wolf/Tula line. It is ever so slightly hotter than the small rifle magnum primer and it comes with a brass colored thick cup. This primer can be used in place of the SRM primer or used when a different powder is used that is hard to ignite."

Primers recommended for use in .223 Rem/5.56 semiautomatic rifle loads:

CCI #41, 450, BR4
Federal 205, 205M
Remington 7 1/2 BR
Winchester WSR
Wolf/Tula SRM
Wolf/Tula SR223

 

[armoredman]

My some day to be aquired BREN 2 MS uses a firing pin spring, so I guess that will alleviate any worries abut my motley collection of primers.

 

[kerreckt]

I have used close to 50k Wolf NC223 primers in the last 6-8 years, almost exclusively in AR15's, with excellent results. They are my go to srp. I have never used a magnum primer loading for AR15's.

 

[Charlie98]

I have never used a magnum primer loading for AR15's.

Again... it depends on what powder you are using, not necessarily what firearm...

 

[Average Joe]

I use small rifle primers in my .223 loads, never had an issue, and I use ball powders. If I ever had a slam fire, I would just tell everybody at the range that I have a full auto gun.

 

[NWcityguy2]

If those Wolf primers are copper color, they are specifically not recommended for ARs.

 

[kerreckt]

Again... it depends on what powder you are using, not necessarily what firearm...

I agree 100%. Even with WC844 I have only used standard primers and have never had any problem. I say this because there seems to be some controversy about which ball powders and which type primers. I have only used large rifle magnum primers with some loads but we aren't discussing large primers so I will stay on topic. Best wishes

 

[jmorris]

I checked my load manuals, and they all call for Small Rifle Primers. He said if I wasn’t sure, then to use Small Rifle Magnum Primers because SRP would cause slamfires.

I imagine you would be better off trusting the load manuals printed information vs someone that tells you to use magnum primers if your not sure.

Load manuals will tell you what primer they used to get the data they have printed.

They will also inform you as to which powders they used magnum primers with and what ones they used standard ones and the use of them has nothing to do with possibility of slam fire.

 

[Charlie98]

Even with WC844 I have only used standard primers and have never had any problem. I say this because there seems to be some controversy about which ball powders and which type primers.

Using a standard primer with a ball powder doesn't mean the cartridge will be a dud, I have used standard primers with H335. From my previous post...

'I have done informal tests with H335 in my AR, using both standard and Magnum primers. Believe it or not, the standard primers produced higher velocity and lower SD's than the 'recommended' Magnum primer... but this was directly related to my specific test conditions, whatever they were at the time, and I did not test for accuracy.'

Note that I mentioned my specific test conditions... those included a mid-range charge fired in a reasonable temperature (70F or so, if memory serves.) Would things have turned out different with 100% case fill, or a compressed load, fired in 20F temperatures? Maybe, maybe not.

There really isn't any controversy...

 

[edwardware]

Slamfires are something to consider in a M1, with its heavy FP, partially effective FP control, and violent feeding. Stoner solved the problems in M16, and no special primers are indicated in AR15s. No thick cups, no magnum primers, nothing.

Seat ye olde SR Primers below flush, and shoot.

Avoid thin-cup primers, like Rem 6 1/2.

Magnum primers are not thicker than non-magnum primers, just louder. Maybe you can fit enough slow powder in a .223 case to benefit from a magnum primer, but I can't.

 

[bihj]

I've used every SRP in production in my AR for years and never had a problem. That is not to say I won't have a problem tomorrow, but up until today, no problems.

 

[NWcityguy2]

I imagine you would be better off trusting the load manuals printed information vs someone that tells you to use magnum primers if your not sure.

Load manuals will tell you what primer they used to get the data they have printed.

They will also inform you as to which powders they used magnum primers with and what ones they used standard ones and the use of them has nothing to do with possibility of slam fire.

This is incorrect. Load data just furnished as 223 load data may or may not be suitable for AR family rifles. Ironically, the rifle stated in your image is a Mini-14. Pressure wise it will be, but primer wise it may not. CCI doesn't randomly recommend that people not use the 400 SR primer in ARs. In my decade as a competitive shooter, and the last 4 years as a certified IDPA SO, I have seen several ARs slamfire using the CCI 400 primer. Sometimes, more than once in a row. I have experienced it myself in an AR with an enhanced recoil spring.

It is also a bit naive to think that one should stick to the specific primers used during testing in a reloading manual. Unless there is a warning against it (CCI 400 / Rem 6 1/2 / Wolf SRP), using different primers in and of itself is not a safety or function concern.

Magnum primers are not thicker than non-magnum primers, just louder. Maybe you can fit enough slow powder in a .223 case to benefit from a magnum primer, but I can't.

Magnum primers may have a thicker cup, harder cup material, some other feature involved, or be more energetic. Or it may be a combination of those things. Literally in this thread someone has quoted CCI in the well-known fact that their SR magnum primers have a thicker cup than their non-magnum SR primer. Also, it is not about where a powder falls on the burn chart. Slower burning powders than what is suitable for 223 can easily be ignited by standard primers.

 

[Mr_Flintstone]

I decided to take a sized case, run it through my RCBS swager, and put in a standard Wolf small rifle primer with no bullet. I then began a test of hand loading this test case into the chamber and releasing the bolt catch; letting the bolt hit the case and primer without the magazine slowing it down. Here are my results.

After chambering once


10 times


25 times


After being manually fired


I’m no expert, but it appears that even though the firing pin makes a slight dimple in the primer, it doesn’t strike nearly hard enough to cause a slamfire, even with the softer primer. I would like to have had some magnum primers to make a comparison, but I don’t have any, and don’t foresee being able to get any for quite some time.

 

[NWcityguy2]

“The Wolf Standard Small Rifle Primers have an all-copper cup, which is a little more sensitive than the brass cup magnum primers. If you are loading for an AR15 or Military-style semi auto rifle, or are loading high pressure cartridges in any other type of rifle, we recommend the Magnum Small Rifle Primers. Both primers use the same amount of compound. The only difference is in the cup hardness.”

http://bulletin.accurateshooter.com/2008/02/wideners-has-russian-small-rifle-magnum-primers/

 

[HowieG]

I just took a look at my copy of the brand new AR Reloading Handbook 2nd Edition by Lyman. They used the Remington 7 1/2 for all the 22 caliber loads listed in their book. That's 223/5.56, 224 Valkyrie, and 22 Nosler.

 

[Otto]

Why would my manuals call for small rifle primers if Magnum primers were needed? Is this an urban legend, or something I should be concerned about? The primers I’m using are Winchester and Wolf.
View attachment 958720

The Wolfs’ are definitely good to go. But with WSR there’s a small risk of pierced primers which erodes the firing pin. FP’s are like $9 so no big deal. Personally, I’d save the WSR primers for pistol loads since SP primers are unobtainable at present.

 

[HowieG]

The Wolfs’ are definitely good to go. But with WSR there’s a small risk of pierced primers which erodes the firing pin. FP’s are like $9 so no big deal. Personally, I’d save the WSR primers for pistol loads since SP primers are unobtainable at present.

I use Winchester Small Rifle primers in my Valkyrie unless am tinkering with match loads. Then I use CCI450. Haven't had any problems with either. Well, actually I don't use anything at the moment. Saving what I have. Perfect gun control is no ammo and no way to make any. Time to buy a bow.

 

[denton]

It is not a matter of what powder you are using.

In my AR, standard CCI primers work just fine for 223 level loads. Increase the powder a bit, and the pressure in the cartridge pushes the firing pin dent back to almost flat. With a little more increase, the primer dent inverts, and makes a little nipple on the primer. With just a trifle more powder, at 5.56 levels, the little nipple breaks off leaving what appears to be a pierced primer. Those little nipples often end up in the mechanism, and cause it to malfunction.

One cure is to shoot 223 loads. The other is to use a primer with a thicker cup, such as the CCI 450 or the #41.

Primers used for .223 Rem. loads should have heavy cups to resist perforation at the high pressures normal for this round. Military 5.56mm primers have a cup thickness of about 0.24", compared to .020" or so that was traditional for the standard small rifle primers. Federal 205, 205M, Remington 7 1/2 BR, Winchester WSR, and CCI BR4, 450, #41, and Wolf/Tula SRM (QQQSRM or KVВ-5,56M) primers have cups of about the same thickness as military primers, and are the best to use when reloading the .223.

Exactly^^^^

 

[Charlie98]

I’m no expert, but it appears that even though the firing pin makes a slight dimple in the primer, it doesn’t strike nearly hard enough to cause a slamfire, even with the softer primer. I would like to have had some magnum primers to make a comparison, but I don’t have any, and don’t foresee being able to get any for quite some time.

Slamfires can be caused by a number of reasons, depending on the firearms, including a stuck firing pin (AR,) a worn safety bridge (M1,) a high primer, debris in the bolt face, etc, etc, not just a floating firing pin.

It is not a matter of what powder you are using.

The need for a Magnum primer is a matter of what powder you are using, the need for a thicker primer cup is not. It just so happens arsenal primers are typically Magnum primers.

 

[Matt Dillon]

I always stick with CCI #41 primers for ALL my AR15 loads.