AR15 Primers

[Mr_Flintstone]

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.

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.

 

[LUCKYDAWG13]

You do not need to use SRM Primers for your AR

 

[BreechFace]

AR’s have floating firing pins and operate on a higher pressure so paying attention to primer cup thickness is important to avoid slam fires and pierced primers repectively. For AR’s I predominately use REM 7-1/2’s, CCI 450’s, CCI BR4’s and CCI #41’s are great as well when one can find them. The CCI #41’s are NATO spec primers for 556.

 

[Charlie98]

The use of Magnum primers is more a matter of which powder you are using, not necessarily the need for it. Ball powders, like H335, recommend Magnum primers because they insure reliable ignition at very cold temperatures. The same is true of a powder like H110... a very slow, pistol ball powder that is typically used in big charges.

For an AR, an 'arsenal' primer like the CCI #41 is recommended because of the floating firing pin. I use them in my AR loads, and the CCI #34 (Large Rifle Arsenal) primer in my .308 loads fired in my M1a and M1 Garand, for the same reasons. Arsenal primers are to be considered Magnum primers in use, however.

What you really need to do is evaluate...

1) What powder are you using?
2) Is your AR serviceable?
3) Are your primers seated at least flush with the case head, or... preferably.... a few thousanths below flush?

If you are using a powder that doesn't require a Magnum primer... something like an IMR powder... and you can seat standard primers at or below flush, and they are used in a clean and serviceable AR... you are good to go.

 

[Jesse Heywood]

The Wolf primers have a harder or thicker cup and are what I have been using in my AR rifles. Magnum primers can be used, but you need to start with load work up at the bottom. And the cup on magnum is usually the same as standards primers.

 

[Mr_Flintstone]

I’m using H4895 and Ramshot TAC with Hornady 55 gr FMJ-BT. My Hornady and Ramshot manuals both call for SRP, and so does Hodgdon online. I always use what the manuals suggest when starting a new cartridge, but I figured better safe than sorry. There’s usually a grain of truth in most stories, but you never know what the actual cause was that started the tale.

 

[Charlie98]

I’m using H4895 and Ramshot TAC with Hornady 55 gr FMJ-BT. My Hornady and Ramshot manuals both call for SRP, and so does Hodgdon online. I always use what the manuals suggest when starting a new cartridge, but I figured better safe than sorry. There’s usually a grain of truth in most stories, but you never know what the actual cause was that started the tale.

TAC is a ball powder, but it is not known to be a stubborn powder, and, of course, H4895 is extruded... so you should be good to go.

If you happen to have a Speer manual... look at the .223 data. You will note an asterisk after powders like H335, BL-C2, and other ball powders... designating a Magnum primer was used in that data. Some data relates this, some does not... but remember, most data is developed under controlled conditions... it is very unlikely they are developing data for H335 in 20F temperatures. 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.

As you say... better safe than sorry. The 'safest' thing you can do is make sure any primer is seated at or below flush, and your bolt and firing pin is clean and serviceable.

 

[hardheart]

Well, does anyone shoot regular commercial 223 out of an AR platform.

Load what you are comfortable with, for reasons that make sense to you.

 

[giggitygiggity]

Has anyone actually had a slamfire in an AR to begin with? If so, was it because of primer choice?

I’ve shot thousand of reloads through my multiple ARs (both factory ARs and one I put together) using an array of SR without any slamfires. My conclusion is that a slamfire is a theoretical possibility, but the likelihood of one occurring is extremely low.

 

[Blue68f100]

Yes to slam fire in a AR-15 and AR-10. The reason I only use CCI #41 or Rem 7 1/2 for the AR-15. Federal are too soft and you will get slam fires. I have not tested any of the Win primers. The CCI #41 have a Mag primer pillow with a modified anvil to reduce sensitivity.

 

[Charlie98]

You will note I kept emphasizing the part about 'a clean and serviceable AR.' There's a reason for that. Generically speaking, a slamfire is most likely to occur for 2 reasons... a gunked up or jammed firing pin protruding when the bolt slams home, and/or a high primer. Yes, the likelihood is extremely low... but people win the lottery all the time.

Drop the bolt on any round of ammo in an AR, then eject it. Very likely you will see a small dimple on the primer... from the firing pin floating forward and striking the primer. Normally, that isn't enough to detonate even a 'sensitive' match primer... but the combination of a number of factors could. I have used standard primers in my AR's... and my M1a and M1, too, without issues, and would if that's what I had... but I'll always circle back to my points noted above in post #4...

 

[Blue68f100]

You will note I kept emphasizing the part about 'a clean and serviceable AR.' There's a reason for that. Generically speaking, a slamfire is most likely to occur for 2 reasons... a gunked up or jammed firing pin protruding when the bolt slams home, and/or a high primer. Yes, the likelihood is extremely low... but people win the lottery all the time.

Drop the bolt on any round of ammo in an AR, then eject it. Very likely you will see a small dimple on the primer... from the firing pin floating forward and striking the primer. Normally, that isn't enough to detonate even a 'sensitive' match primer... but the combination of a number of factors could. I have used standard primers in my AR's... and my M1a and M1, too, without issues, and would if that's what I had... but I'll always circle back to my points noted above in post #4...

Not the case for me. All primers seated below flush, clean BCG. I was testing primers for slam fires. Put a Federal primer and drop the bolt and see what happens. It will likely go off 50% of the time if not more. There are other factors too, such as heavy buffer and springs.

 

[hardheart]

Wondering now what primers LC ammo will use, as Olin Winchester took over production last month. AFAIK they only have one version of SRPs, no magnums nor mil-spec. They have separate magnums for large rifle and small pistol, while their large pistol is marked for both standard and magnum.

https://winchester.com/Products/Ammunition/Components/Primers

I had read somewhere that 7 1/2s were used when Remington ran LC, but I don't know if that's accurate. Win SRPs are supposed to be pretty hot for "standard" primers anyway.

 

[Charlie98]

Wondering now what primers LC ammo will use, as Olin Winchester took over production last month. AFAIK they only have one version of SRPs, no magnums nor mil-spec. They have separate magnums for large rifle and small pistol, while their large pistol is marked for both standard and magnum.

https://winchester.com/Products/Ammunition/Components/Primers

That's an interesting question, and one I wondered about. I don't know if CCI made their arsenal primers at LC (as part of the whole Vista Outdoors gaggle...) or at another facility. If they did, the answer is obvious, but if they didn't, it wouldn't be a terrible stretch to have CCI supply them, or start making them, themselves.

 

[Walkalong]

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.

You are confusing primer mixture strength, standard, or magnum for hard to ignite powders, large charges, or for cold weather or all three, and cup hardness/sensitivity to going off.

A lot of people use mag primers with ball powders in .223, but many don't. Mag primers are not needed with stick powder in .223.

We do want a harder to set off primer in AR 15s to lesson the chance of a slam fire. The Wolf 5.56 SRM (Small Rifle Magnum) primer is confusing because they are a standard primer strength wise, but a harder (Mag) cup for the semi auto AR15 etc.

Copied from Wideners years ago:

SMALL RIFLE PRIMER (part # QQQSR) - Used as a standard small rifle primer. Perfect for the 30 carbine and 223 standard loads. Many people use this primer in bench and other loads for the 223. This primer is a copper colored primer.



SMALL RIFLE MAGNUM PRIMER (part# QQQSRM) - This is the primer we had before for use in the 5.56 loads and hot 223 loads. A thick cup for the higher pressure. We sold a lot of these primers earlier this year. The new lot is brass colored instead of nickel.



SMALL RIFLE 223 (part # QQQSR223) NEW NEW This is the newest primer available in the Wolf 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.

The newer Winchester gold colored SRPs are not as tough as the older nickle plated silver ones. If you have the Wolf Mag primer, that is the better/safer option IMHO.

 

[Mr_Flintstone]

Yes to slam fire in a AR-15 and AR-10. The reason I only use CCI #41 or Rem 7 1/2 for the AR-15. Federal are too soft and you will get slam fires. I have not tested any of the Win primers. The CCI #41 have a Mag primer pillow with a modified anvil to reduce sensitivity.

I wonder what primers Federal uses in their commercial ammo? I have run lots of Federal .223 through my AR with no problems.

 

[hardheart]

I haven't seen their contracts, but I figure a potential big additive reason to pursue them could be that you get to choose your own product to be purchased by the government while you run their production. Given that it meets specification, of course.

 

[Walkalong]

I wonder what primers Federal uses in their commercial ammo?

205s maybe, or maybe their version of a mil spec primer. Email and ask.

 

[Charlie98]

The newer Winchester gold colored SRPs are not as tough as the older nickle plated silver ones.

No, they're not. I've since sworn off them.

 

[MEHavey]

....primers that I should specifically use for .223 in an AR

"AR" is the operative word, not powder type.

Others may pooh-pooh, but I strongly recommend ("less-sensitive/harder cup") Military Primers for any/all floating-pin gas guns
- CCI #41 for small rifles like the AR-15
- CCI#34 for large rifle like AR-10, M-14/M1A, M1-Garand.

 

[armoredman]

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.

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.

I am not the worlds greatest expert in reloading for AR, only been doing it about 3 years, and i always use standard small rifle primers with no issues so far. I also am really anal about making sure the primers are flush, or below flush. No problems yet. Especially now, with no choices but whatever you have in your reloading room right now. .

 

[Blue68f100]

Fed makes a 205MAR primer, I use them in my 6.5 CM (AR-10).

 

[Walkalong]

Fed makes a 205MAR primer,

Which is a recent thing, I sure would love to know if it was an existing primer they used in 5.56, or 205s or 205Ms, or souped up 205/205Ms....... inquiring minds and all.

 

[Swampman]

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.

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

You should be fine with your WSR primers.

Not so much with the Wolf SRP.


As you can see from the above listing of their primer line, Wolf has three types of small rifle Boxer primers.
1- Small Rifle, NCSR
2- Small Rifle - .223 Rem, NC223
3- Small Rifle Magnum, NCSRM

Their bog standard small rifle is analogous to the Remington 6 1/2 SRP. It's designed for lower pressure rounds like .22 Hornet.

Either the Small Rifle - .223 Rem or Small Rifle Magnum primers are fine for .223 loads.

I'm going from 10 year old memories here, but I think the magnum primers are recommended for 5.56 pressure loads.

 

[ms6852]

There is a good article written by John Barsness on primers that may address your questions. The article was written in Guns magazine back in 2009.