Small Rifle Magnum Primers in .223 AR

kbm6893 · Apr 24, 2020

I accidentally bought small rifle magnum primers when I meant to get small rifle primers. Will they even fit in the primer pocket and can they be used in an AR. I got them locally and the guy is nice but I don’t know if he’s going to pull the “can’t accept returns on reloading components”.

rockquarry · Apr 24, 2020

For AR15s, magnum primers are generally recommended over standard primers. Magnum primers have slightly thicker cups and reduce the possibility of a slam fire with such guns and are better suited for higher pressure 5.56 load data. I've used standard and magnum primers in ARs.

Regardless of the gun you're using, magnum primers are fine in .223, just work up load data for that primer.

serger · Apr 24, 2020

You can use them.

growr · Apr 24, 2020

Will fit no problem dimensions are identical, many prefer the magnum primers depending on the type of powder being used...(I use them when I load heavier charges of ball powder).... use them and have a blast!

Randy

kbm6893 · Apr 24, 2020

rockquarry said:
For AR15s, magnum primers are generally recommended over standard primers. Magnum primers have slightly thicker cups and reduce the possibility of a slam fire with such guns and are better suited for higher pressure 5.56 load data. I've used standard and magnum primers in ARs.

Regardless of the gun you're using, magnum primers are fine in .223, just work up load data for that primer.

Thanks. I did a little research waiting for a response here and was told the same. Whew!! Damn CCI boxes look so much alike. I'm loading just over minimum anyway. 26.3 grains of CFE 223. Minimum load is 26 grains.

Should I separate them in my ammo box if powder is the same?

growr · Apr 24, 2020

Few would be able to notice any difference.....I can't tell. Prairie dogs aren't going to tell either!

Randy

rockquarry · Apr 24, 2020

kbm6893 said:
Thanks. I did a little research waiting for a response here and was told the same. Whew!! Damn CCI boxes look so much alike. I'm loading just over minimum anyway. 26.3 grains of CFE 223. Minimum load is 26 grains.

Should I separate them in my ammo box if powder is the same?

I would, but that's really up to you. Check point of impact; they could be a little different and if they are you wouldn't want to mix them. However, I would bet that point of impact for both will likely be about the same and so will muzzle velocity.

lrrifleman · Apr 24, 2020

kbm,

What bullet are you loading?

kbm6893 · Apr 24, 2020

lrrifleman said:
kbm,

What bullet are you loading?

55 grain FMJ from .223bulkbullets.com. Shot from M&P Sport 2

Univibe · Apr 24, 2020

No. CCI #41 only. They have a harder cup, which is needed because the AR firing pin has no spring.

rockquarry · Apr 24, 2020

Univibe said:
No. CCI #41 only. They have a harder cup, which is needed because the AR firing pin has no spring.

Another good primer, but certainly not the only one.

TjB101 · Apr 24, 2020

I usually load 25.7gr of Varget with SRP primer for one of my rifles.. Drop to 25.0 with SRM primers.

boatbum101 · Apr 25, 2020

CCI #41 is milspec , Rem 7 1/2 also good mag primer . Some also use the CCI 400 ( IIRC ) . I use the Rem as they're cheaper than the # 41's .

jimbo728 · Apr 29, 2020

Im stuck on using 24.6 gr of Varget. MOA to sub MOA in a 1in8 twist early Sport The 55 gr bulk bullets do surprisingly well with that load.
Good Luck on your rifle loading!
Jim

SMSgt · Apr 29, 2020

Univibe said:
No. CCI #41 only. They have a harder cup, which is needed because the AR firing pin has no spring.

If you check with CCI, it will tell you the difference with the #41 is a larger gap between the anvil and cup, not the thickness or hardness of the cup.

CCI/Speer Technical Services says: "The CCI 400 primer does have a thinner cup bottom than CCI 450, #41 or BR4 primers... [with] the CCI #41 primer... there is more 'distance' between the tip of the anvil and the bottom of the cup."

Note it does not state the #41 cup is thicker, just that the 400 is thinner than others.

gwpercle · Apr 29, 2020

kbm6893 said:
Thanks. I did a little research waiting for a response here and was told the same. Whew!! Damn CCI boxes look so much alike. I'm loading just over minimum anyway. 26.3 grains of CFE 223. Minimum load is 26 grains.

Should I separate them in my ammo box if powder is the same?

I would separate them just out of trying to keep boxes of loads as consistent as possible .
You just may discover the magnum primers might tighten up your groups ... if they are all mixed in with regular primer loads you would never know .
Sometimes a change in primers can improve a so-so load into a tack driver . Test them for accuracy and see how they do .
Gary

rockquarry · Apr 29, 2020

My testing of primers for .223 handloads has not been extensive, but I did some comparisons in the last year using a favorite bullet, the Sierra 65 GameKing and three primers, CCI-400, CCI-450, and the Remington 7 1/2. Powder was H4895. A couple of Colt AR15s with 7" twist bores and a CZ bolt-action with a 1 in 9" bore were used.

Without reviewing my notes, I'll say that generally the CCI-400 showed best accuracy, but this became a hair-splitting exercise. The CCI-450 and the Remington 7 1/2 were very close. I'd feel confident using any of these primers.

My guns are not target guns, but rather stock out-of-the-box shooters, no trigger jobs, replacement parts, etc. except for scope sights. With the ARs, I can get one inch five-shot groups at 100 yards on occasion, but not every time like the Internet guys with the "all day long" rifles. The CZ is more accurate than the ARs.

It's worth trying different primers and five-shot groups fired at 200 yards on a very calm day will tell you more than 100 yard groups.

LostintheOzone · Apr 29, 2020

growr said:
Will fit no problem dimensions are identical, many prefer the magnum primers depending on the type of powder being used...(I use them when I load heavier charges of ball powder).... use them and have a blast!

Randy

Yeah, what he said about ball powder. I just bought some ball powder so those old mag primers are finally going to be used up. Normally I just used std SRP for stick powder loading .223. Works just fine and I shoot a 1 MOA rifle.

fredj338 · Apr 29, 2020

I think it has been covered but many loads for semis in 223 will say to sue a mag primer. It is all I run in my AR loads.

Small Rifle Magnum Primers in .223 AR

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