Primers

I’ve read a little about primers but have a question for the people in the know. I have used large pistol primers in my 44 mag with decent results, at least no failures or surprises. I will be buying magnum primers from now on for it. My question is if I use magnum primers in 45 ACP will it be a problem? Just trying to learn a little. The fewer choices I have the less likely I am to make a mistake.

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should not be an issue, I use which ever ones I can get for rifle and pistol…depending on the load and bullet type/weight magnum primers are often the ones to use.

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Magnum primers tend to be a little hotter than standard primers. This is because the powders used in magnums have a slower burn rate. You want a uniform ignition of the powder in the cartridge to get a consistent chamber pressure. Magnum powders can in theory not ignite as consistent as faster powders. Hence the need for a hotter spark. Consistent chamber pressure leads to consistent hits down range. With that out of the way magnum primers in standard loads in theory give you higher chamber pressures. Probably not enough to destroy your gun just stay away from max loads with magnum primers in nonmagnum loads.

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Rumor has it that Winchester primers are pretty much all magnum weather labeled as or not. In fact their large pistol primers are labeled for standard or magnum loads.

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I never noticed until now.

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I had a little time today so I did a little reading on searches about the subject. Seems that most say that if you use magnum primers in regular loads to cut the charge by 10% to make sure you don’t get too high a pressure. I was mainly curious. Now I have a little more info. Next is how does using non magnum primers in say a 44 mag perform?

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But you wanted a single primer to avoid possible mistakes, now you replace two sets of primers with being sure to cut the load?

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Inconsistent powder ignition. non linear powder burn in the cartridge causes unpredictable chamber pressure. chamber pressure consistency is key to repeatable accuracy.

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I’m not sure what you are asking. As I keep reading and learning I will use the primer that is correct for the load. I’ve always been a tinkerer, but in reloading safety is king so I won’t be doing much tinkering.

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I wasn’t asking so much as pointing out you started off IMO seeking to reduce the primers on hand to avoid mistakes, then introduced a formula that IMO that could create a mistake

Or so it seemed to me :slightly_smiling_face:

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:thinking: now I’m confused

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No, I wasn’t trying to reduce inventory. I just had a question about the technical difference between small rifle and small pistol primers. Also will the small pistol primers be adequate for the 30 carbine middle of the road load using H110 powder.

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I all pretty much boils down to how desperate you are. While the world is still turning you should use the recommended primer for the application. If SHTF :shitfan: then you got to do what you got to do. I don’t recommend experimenting until you know a little more about powder ignition and pressure curves. The boom parts of ammo are not a linear equation they are exponential until you understand all these things stick with published data. You can try QuickLoad for simulated data but, that’s all QuickLoad is, it’s a simulation not real world data like published loads from a reputable source.

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Thanks, I don’t plan to do any experimenting. Just trying to learn. Still looking to see if anyone knows the difference in the charge between the two primers. I just would like to know.

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Here are my rules for this…

  1. Never use magnum primers in 380 ACP, 9mm, 38 Super, or 40 S&W.
  2. Never use magnum primers with fast burning powder in any cartridge.
  3. With medium burn rate powder in a 38 Special, 44 Special, or 45 Colt, magnum primers can be used if you lower the powder charge weight by .5 grains.
  4. Always use magnum primers with slow burning powder such as H-110, W-296, Lil’Gun, or IMR 4227.
  5. do not use the wrong primers unless the world is ending
  6. none of this is professional advice
  7. reduce your powder load by 5 to 10% for safety when experimenting.
  8. you do this at your own risk.
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It’s not a charge difference between primers like powder charges. It’s more like a difference between fast powder and slow powder. We can’t give you an equation to follow. To do the thing’s you are talking about is experimentation. It can be done safely but you need to do it slowly and carefully monitor the pressure signs. Heck back in these day people used to pack slow powder on top of fast powder.

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Hey, that’s my job! :rofl:

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I don’t want to discourage you, it’s a reasonable question it just doesn’t have a simple answer.

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I enjoyed this topic and learned some myself

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If I read you right, one primer burns faster than the other but the bang is the same.

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