296 and non-magnum primers

[XD-40 Shooter]

I had a brain fart today and loaded 10 rounds of 357 mag/158 grain JHP with 16.6 grains of 296, but I forgot to use the magnum primers, I accidently used my standard primers. Are these rounds still safe to shoot, or should I chuck'em? From now on, I'll be sure to use the magnum primers.

 

[Ol` Joe]

I used STD LP primers in my M29 44 mag with H110/240 gr lead loads and had no problems, I doubt you will either.

 

[Mal H]

The odds of having an incident with them is very, very small. If it were me, I'd shoot 'em, but maybe keep a weather ear open for a squib (highly unlikely to happen).

 

[Sunray]

Magnum primers burn a bit hotter for a bit longer. They're for lighting hard to ignite powders and in extreme cold weather. You don't need magnum primers just because you're loading a magnum cartridge. You only need them if your manual says to use them.
"...a squib..." That's a load without powder or not enough powder. It's got nothing to do with what primer you use.

 

[Grumulkin]

Using a standard primer will not cause high pressure and in a case the size of a 357 Magnum, should burn Win. 296 just fine. I would have no worry at all about shooting them.

You might check the accuracy though. Sometimes standard primers give better accuracy than the magnum version.

 

[eldon519]

I use standard primers with my H-110 Ruger .45 Colt loads. No problems here.

 

[zxcvbob]

They are probably safe to fire if, like MalH said, you are careful to watch out for a squib. But why tempt fate? It's only 10 cartridges. Pull the bullets, dump the powder back in the hopper, and reload them with Herco or Unique or 2400 or 231. Or if you don't want to mess with the powder measure, use a compressed charge of pyrodex or 777 or black powder. You don't have to measure those, just fill the case.

I recently pulled the bullets from a hundred 9mm rounds that I loaded with 5 grains of powder instead of 4.5 grain. 5 was probably safe to shoot, barely, but I'm hoping I learned a lesson from this exercise (doublecheck your load data *before* loading instead of after)

Bob

 

[zxcvbob]

Eldon, those are large primers. .357 uses small primers. I'm pretty sure the large primers are hotter.

 

[Phil A]

I have found that magnum primers with slower powders makes a difference with the .357. We are talking small pistol primers here. I have not noticed this with the large pistol primers (ie. 44 mag). I got inconsistent ignition and velocities with H110/296 and AA7 using std small pistol primers. You might experience some excessive powder getting blown out of the gap. - Phil

 

[Mal H]

"...a squib..." That's a load without powder or not enough powder. It's got nothing to do with what primer you use.

No, not entirely. There is a known history of squib loads when using both W296 and H110 (essentially the same powder). The squib occurs most often when using a standard primer and usually includes a light crimp. Those conditions can cause the mentioned powders to fail to ignite completely. The OP's use of W296 is the only reason I mentioned the slim possibility of a squib load.