magnum primers ?

[rebs]

I load some 223 with H335 @ 25.0 gr with a 55 gr bullet and it is safe to shoot. What exactly happens if I used a magnum primer with this load ? Will velocity increase and will pressure increase ? This is for shooting in an AR.

[steveno]

how close to max is your load now? if it is max you would probably need to back off a little bit and work back up. if you have a chronograph load up 10 rounds or so and compare them with the standard primers.

[GeauxTide]

+1 Stevereno.....

[rebs]

The loads are 25.0 of H335 with a 55 gr bullet
27.3 of CFE223 with a 55 gr bullet
with LC brass and fired in an AR

[mikld]

The loads are 25.0 of H335 with a 55 gr bullet
27.3 of CFE223 with a 55 gr bullet
with LC brass and fired in an AR

What are the max. charges?

[Snyper]

Will velocity increase and will pressure increase ?

You'd probably see very little difference in either.

[T. O'Heir]

25.0 of H335 is close to max, but nothing bad will happen using a magnum primer. Pressure might go up a tick(PSI of 49,300 with a max load of 25.3. A TSX gives 53,000 psi. with less powder.) but not enough to worry about. However, you will most likely see a change in POI and maybe accuracy just by changing the primer.

[Catfish]

I once did so experimentation with primers. I would load the same powder and bullet with several different primers and check them for pressure signs and velocity. The only thing I found is that you never know what a different primer will do. I had 1 load that that with 5 different primers had an extreme spread of 5 fps. I had another load that 1 primer showed signs of extreme pressure, and it was a standard and not a mag. primer. Different primers work differently with different powders and from what I saw I would recommend starting low and working up your load every time you change primers, whether going from a standard to a mag, or the reverse, or just another brand.

[Darren007]

Unless you own a chronograph, I wouldn't bother.

[oley55]

I use CCI #41 primers with 24.9gr of H335 for 55gr bullets all the time.

Lots of folks say CCI #41's are mag primers with a harder cup, but have never seen poof of that.

[TimSr]

Not many loads for a small rifle primer that actually calls for a magnum, which is why some primer companies don't even make them.

[Marco Califo]

Magnum primers are recommended for autoloader rifles to minimize risk of slamfires. I use CCI#41 and Russian 5.56m exclusively for 223. Mostly bolt rifles. You will need to work up with them, but you will NOT see a huge difference. H335 and CFE223 are both ball powders and should actually benefit from the magnum primers with greater consistency.
I dont use CCI #400 anymore because I pierced primers more than I wanted.

[tcoz]

H335 is a spherical powder and per Hodgdon tech support, magnum primers are recommended with all spherical powders as they are coated to slightly retard ignition. I use CCI NATO primers (41 & 34) in my semi autos. They're magnum strength primers with a slightly thicker cup, developed for the military in an effort to help prevent slam fires.

[Nosler guy]

Magnum primers are usually best to use in a non magnum gun if you're shooting ball powder, which is hard to ignite, and said powder isn't burning completely before the bullet leaves the muzzle. It will up pressure a bit and other than having a powder burn issue it probably won't make performance better. As far as testing multiple primers with the same load and getting extreme pressure signs, you're most likely using brass with different volumes.

[res45]

I use CCI #41 primers with 24.9gr of H335 for 55gr bullets all the time.

Lots of folks say CCI #41's are mag primers with a harder cup, but have never seen poof of that.

http://www.cci-ammunition.com/produc...ers.aspx?id=30


Features & Benefits

Mil-spec sensitivity
Initiator mix optimized for ball/spherical propellants
Available in large (No.34) and small (No. 41) rifle
Use the same data as CCI Magnum primers
Military-style semi-automatic rifles

Primer Info and Chart,each primer category is broken down with cup thickness as well as other specifications.
http://www.sksboards.com/smf/?topic=56422.0

[tcoz]

I want to slightly correct what I stated in post #13 above. CCI 34 & 41 NATO primers do have a thicker cup than standard primers, but the BR4 and CCI450 primers also have this thicker cup. Where the mil-spec primers do differ from the others is that there is a slightly greater distance between the bottom of the anvil and the primer cup. This is where their resistance to slam fires enters the picture. They won't by any means prevent slam fires, but they can make an out of spec rifle more resistant to them.
Of course, the biggest cause of slam fires is improperly seated primers.

[Unclenick]

Catfish has it right. There's no way to know without trying. As QuickLOAD author, Hartmut Broemel points out, there are some scenarios in which a magnum primer can actually lower peak pressure and velocity. Charles Petty, in a 1996 article in Handloader, showed the same 55 grain .224 bullet in a .223 rifle with the same charge of Reloader 10X went 3150 fps to 3300 fps by varying primers, with a magnum bench rest primer responsible for the highest pressure and velocity. So it just depends which primer and powder and bullet combination you choose.

What a magnum primer does that is different from a standard primer is produce a higher volume of gas. That is to better pressurize a larger magnum case in order to have adequate start pressure. Some primers do this with more fuel compound, raising pressure but lowering brissance, thereby producing the gas more slowly. Others just use a larger quantity of their standard priming compound, and those tend to run everything hotter. Some powders, like the older St. Marks Western Canon (WC) series of spherical propellants (H335 is one of them; St. Marks WC844 in bulk form) have heavy deterrent coatings that are hard to ignite. Allan Jones, who worked for CCI, points out CCI reformulated their magnum primers in 1989 specifically to better ignite those old spherical powder formulations. This doesn't necessarily hold for newer spherical powders. More modern deterrent coatings, such as are used on the Ramshot line of powders, do not need that extra ignition effort. Western Powders says standard primers work just fine with the Ramshot line.

The bottom line here is that the proof is in the pudding. Start low and work up to a best accuracy load. Do that with each primer under consideration. Assuming the accuracy of the best loads for each primer at short range (100 yards) is similar, then look at velocity extreme spread for each. Then the primer producing the lowest extreme velocity spread is going to be most accurate at long range.

Originally Posted by Oley55

Lots of folks say CCI #41's are mag primers with a harder cup, but have never seen poof of that.

Dude! You just need to give it a try! All it takes is a telephone or email. I simply called CCI and asked. What they told me was the cup and priming mix and the priming mix quantity in the #41 are identical to their CCI 450 magnum small rifle primer. The difference between the two is the anvil in the #41 is shorter and has a wider angle to its legs, and that's what reduces its sensitivity to military spec levels.

Tcoz,

You're spreading rumors, too. CCI told me directly that the #34 is identical to a CCI 250 in priming mix and cup thickness. Again, the difference is the anvil geometry.

Military specs:



Federal is different. Their GMM205MAR is, they told (email this time) identical to the 205M (not a magnum primer) except the cup is thicker to get to the military spec.

Guys, it doesn't take but a call or email to verify the facts. Let's at least make a little effort to double-check before deciding what to believe and pass along to others. Good information is always best.

[tcoz]

Unclenick, I'm not spreading any rumors. You must have read post #13 but not post #16 where I corrected myself. I said that CCI NATO primers (34 & 41) have a thicker cup than STANDARD primers but that the 450 and BR4 also have the thicker cup. I just didn't mention the 250s. I also said, as you did, that the difference between the NATO primers and magnum primers is the distance between the anvil and the cup is greater.
No rumors there....we said exactly the same thing.

[Unclenick]

Tcoz,

Sorry. I think I read the thread in the morning and left it in the browser window while work took me away, so I didn't see your addition. Should have looked. My bad.

This subject has come up repeatedly, so I'm thinking maybe I should put a sticky up as a reference.

[tcoz]

Unclenick,
No problem at all. This subject does come up repeatedly, on every forum I read. There always seems to be a lot of confusion and very few people have the correct information. A sticky would be a good idea. I've seen a diagram indicating the various primer dimensions along with a corresponding chart listing these dimensions for various commonly used primers. You've probably seen it as well, but if not, I'd be happy to find it and send it to you to be included in the sticky. PM me if you need it.

[E Rick]

I have Lymans 47 new edition reloading handbook and on page 200 it says to use small rifle magnum primers in .223 Remington. All my other books just say to use small rifle primers. I use both and have not had a problem.

[sicumj]

Yep magnum primers are what you SHOULD be using for that application.

[Louca]

I use CCI 450 magnum primers in LC brass to lite 24.5 gn of H335 to push a 55 gn Sierra Blitz King in a 1:8 NM AR. Things work well and no signs of excessive pressure.

[rebs]

I use CCI 450 magnum primers in LC brass to lite 24.5 gn of H335 to push a 55 gn Sierra Blitz King in a 1:8 NM AR. Things work well and no signs of excessive pressure.

Is that load where you found your best accuracy ?

[Slamfire]

In so far as primer characteristics primer manufacturers can vary primer cake sensitivity, cup thickness, and anvil characteristics.

Picatinny Arsenal document, PATR 2700, says this about primer sensitivity:

The sensitivity of a primer for a given firing pin/weapon system is then designed into the primer by the proper choice of the thickness of the base of the primer cut, the point radius of the anvil, and the degree of compression of the mixture between the anvil point and the cup. This is controlled by the degree to which the anvil is compressed into the cup during manufacture of the primer. In addition, some influence of further compression can be achieved when the primer is inserted into the cartridge case and crimped.

So, here Picatinny is telling us the primer manufacturer can change cup thickness, anvil tip shape, and anvil/primer cup distance, given a fixed primer cake composition. Generally speaking, primer cake composition is kept constant by the manufacturer. It was hard enough for these guys to come up with a good primer mix and they don't like to monkey around with something that works.

FA 956 is a small arms primer composition that came out of a joint industry and military cooperation program in the 1950's.

PATR 2700 Encyclopedia of Explosives gives the composition

FA 956

Lead Styphanate 37.7 +/- 5%
Tetracene 4.0 +/- 1%
Barium Nitrate 32.0 +/- 5%
Antimony Sulfide 15.0 +/- 2%
Aluminum Powder 7.0 +/- 1%
PETN 5.0 +/- 1%
Gum Arabic 0.2%


There are plenty of primer compositions for there are many applications for primers other than small arms. This is a list of military priming mixtures, FA 70 is the old corrosive 30 cal primer, FA 90 was the corrosive 50 cal primer. I was able to identify PA101 as a fuse primer composition. All of the compositions to the right of FA90 are more sensitive than rifle primer compositions, so these are probably used on a variety of explosive or propellant devices.




Commercial manufacturers are free to vary what ever they like, but they try to stay within SAAMI boundaries for sensitivity. When they are making military ammunition, they have to meet contract requirements. It is likely military primer characteristics are still as what Unclenick has posted. If the military ammunition maker creates ammunition where the primers are so sensitive that it causes doubling, slamfires, or out of battery slamfires, the Military has the resources to pursue legal penalties. I have never heard of a civil suit by a civilian brought against an ammunition maker for damages caused by overly sensitive primers. Individuals don't have the money to sue a multi-billion dollar Corporate entity, such as ATK, and win.


In the book, "Ammunition Making", by Frost, the author provides cup thicknesses for pistol and rifle ammunition, and Frost provides dimensions that show the military cup is thicker. So whatever manufacturer he was working for, they were making the cup thicker, and maybe there were some other manufacturer's doing the same thing.

Information on primer characteristics has been very hard to acquire. American corporations don't make money educating us, in fact, they like to keep us stupid, as our ignorance becomes their strength. Ignorant people are easily swayed by superstition, emotional appeals, and misinformation. Educated people are harder to manipulate. So what you find is very little information in the public domain, and what is there, is either advertising, which is unreliable, or very old military technical data, which may not be current or relevant. The absolute best book I have found on primers is George Frost's book Ammunition Making. The author even tells you how to make you own primer cake, and he provides all sorts of primer sensitivity data. I am glad I bought that book when it first came out, as it is out of print and prices on Amazon are ridiculous. Knowledge is not cheap, but ignorance is free.