I have a new can of Winchester 231.I would like to us it for 357.mag. some of the loads call for magnum small pistol primers. I don't have any mag primers .is there a danger in using standard primers.

No. Magnum primers are very helpful for good ignition of relatively large charges of relatively slow powder. Using a standard primer might give you a little LESS pressure and depending on the load and powder and weapon maybe a little more unburnt powder. No hazard though.

231 has been one of the fastest powders made. Hard to believe someone would print loading data recommending a mag primer.

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"Don't Give Up the Ship"

Most loading manuals specify magnum primers for all loads in the .357 magnum because of the tall case. Small rifle primers are basically identical to small pistol magnum primers.

I've never used magnum primers in my 357 loads using fast or medium burning powders. I have heard that magnum primers may have a small benefit in terms of igniting fast powders in the longer cartridge, but they are not required. For slow powders like AA#9, HS-6, H-110/W-296, magnum primers are a must.

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VCDL, GOA, NRA

I wouldn’t (and didn’t) use magnum primers. I shot tons of 158 grain lead RN and SWCs with 6.5 of 231. Great load at about 1,000 fps, so not a full magnum load.

I think the general consensus is that magnum primers should be used with ball powder. I use std primers in all my 357 and 30 carbine loads with 2400, which isn't a ball powder.

I think W231 is a ball powder so maybe that's why some manuals call for mag primers.

Personally I don't think I've ever heard of anyone using std primers having any problems with W231 to load .357.

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That's just somebody talkin.

There is no need for a magnum primer with 231 in a .357, IMHO - or at least I have never seen or heard of a need. I wonder if they didn’t specify it just because they used the same primer for everything else in their .357 data? I have been using 231 with Federal 100 primers in moderate .357 loads for years, if not decades. Never saw any indication that made me think a magnum primer might offer an improvement.

In my limited experience, I have loaded tons of 41 Mag with 20 grains of H110 and standard primers with absolutely no ill effects and any velocity difference was not noticeable. In theory you may have some unburnt powder but I haven't personally experienced that with H110. Of course other's experiences will vary but for sure, you won't be doing something unsafe.

Most reloading manuals will recommend a magnum primer for magnum cartridges no matter which powder they list.

OP,
As said above, W231 does not need a magnum primer to ignite correctly. Now W296 is a different story, a magnum primer works much better. No danger at all.

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Freedom is never free!!
SWCA #3437

Hard to understand why you would want to use std primers with H110. Nowhere in any load manual or magazine article will you see std primers recommended with H110/296. Depending on your bullet and the length of your gun barrel you are probably only getting around 1050-1100 FPS out of your 41 “magnum” load. You don’t notice any velocity loss for one reason, you don’t have a chronograph. You could use 9.5-10 grs of Longshot or Autocomp and save 50% on powder cost. OR...get some magnum primers and get magnum velocity.

The unburnt powder gets blown out of the gun and ends up on the ground. That's why you haven't seen it. Like one of the other posters said, if you chronograph that load you will see a big difference with the magnum primers. I agree that it's not unsafe but it is very inefficient.

If you have any winchester standard primers......

they were designed for "Ball powder" and run a little hotter than the other standard primers, so that they will work with the companies powders.

I also used their magnum primers but find that they were not needed with my loads and weapons
to gain any advantage in my loads and powders use over the years of testing.

However, a magnum primer with ball powder is not a bad idea, to get 100% burn and maybe a cleaner shooting table
if you use the very slow burning powders, if using the other brand primers.

Just to further the discussion, I shot a bunch o non-canister equivalent to Accurate #9 in a wildcat based on the 357 Mag case tapered to .319. It used lead bullets fired just subsonic from a custom single shot bench gun. My primers of preference were Federal SR Match. This combination shot cleanly and accurately in my rifle, but this discussion got me wondering about the relative strength of these primers vs the others under discussion.

Froggie

If it ain't broke, don't fix it.

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That's just somebody talkin.

I thought at one time the...........

Thread Index

had a fact sheet with the different primers and their properties

from cool to hottest flame ?

Later.

Plain and simple, Ball Type Powder. Reliable consistent ignition across the entire spectrum.

Look at any older Speer manual and you'll see their test commonly use magnum primers with non magnum calibers using BTP's. Speer testing shows some combos even low pressure low velocity loads using BTP's are more consistent with magnum primers.

Do I use magnum primers with HP38/W231? Rarely, if ever but I know why some data recommends it.

Especially in rifle loads, I use magnum primers more often than not now. Even though I use a lot of extruded like IMR4064, 4350, 4831, I like W760/H414, W748, H335, Accurate 2520 etc, and it's easier to keep one type primer on hand. I still test accuracy using test both standard and magnum, if there's little to no difference I generally use the magnum large rifle to work up my loads.

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It's A Sight, Ain't It...

There is a lot of information out there regarding the use of small rifle primers in place of small pistol magnums. For CCI at least, the two appear to be the same product in a different package.

This is not a recommendation, just a possible avenue to research.

This video is well worth watching if considering interchanging primers when reloading. Facts over opinion is the only way to go.

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Gary
SWCA 2515

Absolutely, and to further put a point on it, CCI has a BYOP (bring your own primers) program where you supply the primers and they make factory reloads for you. They will load your ammo with SPP, SMP, or SRP primers for you - whatever you have to give them.
That means they are accepting the liability of loading ammo with the "wrong" primers. Think they'd do that if there was ANY appreciable difference? Obviously the answer is a big NO WAY.

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Send lawyers, guns & money...

I love that we have some hard data rather than a bunch of conjecture at this point. Thanks for posting that video!

Nice test. No significant difference in pressure generation, but differences in cup metal alloy, small pistol being the softest, rifle being the hardest. I have long heard this, nice to see proof from one of the manufacturers.

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VCDL, GOA, NRA

For conventional small capacity, reasonably high load density handgun rounds I agree there is virtually no difference between small primers beyond potential light strike issues (with the exception of magnum rifle primers). However, in terms of light strike issues there can be differences even between brands.

For example one of my S&W revolvers has a marginal hammer spring that is 100% reliable with CCI 500 primers but has occasional light strikes with Winchester WSP primers.

——

Where primer brisance starts to matter is in rifle rounds, in terms of accuracy and to some extent safety, and potentially in some of the older high capacity low load density cartridges, like the .38 Special

For example the .22 Hornet in general is an exceptionally accurate round, but many .22 Hornet shooters get even better accuracy with small standard pistol primers. It makes sense, as the case capacity is quite small, and the pressure is low enough that the lighter cup doesn’t pose any issues.

At the same time, I’ve measured average velocities and higher standard deviation in velocities using magnum small rifle primers in the .22 Hornet - on the order of 75 FPS faster with some loads and with some obvious pressure signs. In that particular instance with some powders it makes a significant difference. Enough that if I do another batch of .22 Hornet using small rifle primers, I’ll take the precaution of working up a load to my target velocity using the rifle primers.

At the other end of the spectrum, large capacity rifle cases using some of the harder to ignite powders really do need a magnum primer for consistent ignition and to avoid hang fires.

Accuracy wise, primer brisance also effects how much the powder is scattered in low density loads and too much primer with a low load density can create pressure spikes.

That increased scattering of powder in high volume cases like the .38 Special (which was originally designed as a black powder case and has way more volume than it needs for smokeless powder). Excessive primer brisance can potentially create pressure spikes with the very low load density loads you often have with some of the fast flake powders.

——-

The point here is don’t over generalize the results in 9mm cartridges to and other pistol rounds to the entire range of rifle rounds or think you can use a magnum small rifle primer, or a large rifle primer of any type.

(See my post on Supervel’s BYOP program below.)

I have not heard of CCIs BYOP program. Can you share a link?

——-

Supervel has a BYOP program although it has some important limits you need to understand before you start mixing and matching primers.

The BYOP program is limited to certain pistol cartridges:

- 9mm 115 gr FMJ;
- 9mm 124 gr FMJ;
- 9mm 147 gr;
- .40 S&W 180 gr FMJ; and
- .45 ACP 230 gr FMJ.

Also bear in mind the primers they allow are:

- small pistol;
- small magnum pistol; or
- small rifle.

For .45 ACP they only allow large pistol or magnum pistol primers - no rifle primers.

They *do not* allow small magnum rifle primers, nor the NATO equivalent in the 9mm or .40 S&W or large rifle in the .45 ACP.

Finally, they limit primers to the following brands:
-CCI,
-Federal,
- Remington,
- GINEX,
- GENEX,
- Magtech,
- FIOCCHI,
- Murom, or
- Sellier and Bellot.

——

In short, they swap primers for selected loads in reasonably small capacity, high load density cartridges using a powder or powders that are not primer sensitive, with strict limits primer types and brands.

BYOP Program

Interesting video. It pretty much confirms my suspicions, but it’s more of a demonstration than a real scientific test.

I have never understood calling 231 a ball powder. It looks nothing like, for example, AA5 or Ball C2, or any other powder I normally think of as a ball powder. If it’s a “flattened” ball, then isn’t it, for ignition purposes, really no longer a ball? Well anyway, I remain with the “no need of a magnum primer with 231” camp. My chronograph has never shown any improvement in ES or SD with magnum primers, and in some cases has shown the opposite, so what few I have are getting old and don’t get used.

I recently tried something similar with my .300 Weatherby and Reloader 25 powder. It’s a big charge of very slow burning powder in a long, thin case. I used Federal 215s and standard Winchester large rifle primers (not the ones marked for “standard or magnum” loads). I have no pressure measuring equipment and I don’t have the chronograph readings or targets handy right now, but I saw very little difference in ES and SD, and accuracy at 100 yards. I only fired 3 rounds of each, so, again, not much of a test. Temperature was about 85 degrees F.

These very limited tests, like mine and the one in the video, really don’t stand up to much scrutiny. But they are what they are.