# Magnum Primers vs Standard Primers



## david2729 (Jan 9, 2010)

I am getting into reloading and have noticed a shortage of pistol and rifle primers. I visited one of my reloading suppliers and they have all kinds of rifle and pistol primers but they are all mangum primers. One of the gentlemen that works the counter told me that I could use CCI 550 primers for my pistols (Glocks & Sigs, 9mm's, .357 Sig & 40 S&W) and all I would have to do is stay with the less than maximum recommended loads and reduce the load by 3/10th of a grain. I have Lone Wolf Match barrels for all my Glocks for full cartridge support in shooting reloads. I'm kind of a cautious person and don't want to take one person's thoughts on this subject and was wanting to know if anyone has used magnum primers in loads requiring small pistol primers. I don't want to do something stupid and blow myself up.


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## Csquared (Sep 5, 2006)

You're not going to "blow yourself up" !

Any time you change a component in a load, even lot number of powder, you _should_ reduce the load slightly and work back up, but I wouldn't let lack of standard primers to keep me from shooting. I expect the gentleman you spoke with is fairly well versed, although I think you might find a reduction of a bit more than .3 grain recommended.....depending on your load.

Search the various loading manuals and chances are you will stumble across some that use magnum primers anyway. I seem to remember data that shows both for the same cartridge.

Welcome to the site. Lots of very smart people here. And it sounds like you're already adept at sorting those from the rest


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## d'Artagnan (Jan 13, 2007)

On another forum I described in detail what happened when I substituted Winchester small pistol magnum primers in my standard 9mm load. To summarize, without changing anything else, substituting the magnum primer will get you 5% greater muzzle velocity (mv). If you want the mv to remain the same with magnum primers, drop the powder load about 16%.


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