Magnum primers vs. regular primers


April 21, 2008, 09:18 AM
Can I use magnum small pistol primers in place of (regular) small pistol primers.

I reload for .357mag/.38 special. I have a very limited amount of .357 brass but a boatload of .38 brass. I was able to acquire near 1000 magnum primers at a good price.

So can I use the mag primer in .38 specials?

Dumb question probably but I have been unable to find an answer by using "search".


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April 21, 2008, 09:34 AM
Without getting into a spitting contest with other reloaders I am going to make just two statements.
1. Standard primers are normally used with fast burning powder and usually lead or jacketed bullets. Magnum primers are used with slower burning powders and usually heavier jacketed bullets. Standard 38 Special loads use standard primers and 357 loads normally use magnum primers.
2. I suggest you check 2 or 3 reloading manuals(the more the better) and follow whatever is recommended for your powder and bullet.
Good shooting. :)

April 21, 2008, 09:42 AM
It has always been told to me that if you use magnums you need to restart at the bottom and load up form there... Keep checking for bad signs until you reach your desired group or until said bad signs are seen.. Then stop there...

April 21, 2008, 12:24 PM
Follow established reloading data!
If it states use small mag pistol primers then use them, but for the most part when you change out any component of a load you should start over as you changed the parameters....

April 21, 2008, 03:12 PM
thanks for replies.

I suppose it is not worth risking damage to myself or the gun. i will just keep reloading the mags as I shoot them. I'll worry about .38's when I acquire some regular primers.

evan price
April 22, 2008, 02:21 AM
It won't hurt your gun. The only difference between Magnum and Standard primers is that the priming compound in Magnums burns hotter and flashes farther. This is to ignite slow bulky Magnum powders better.
You can use Magnum primers in regular loads just drop your powder by .1 or .2 grains to compensate.
I use nonMagnum primers for my Magnum loads (of course I use fast powder).
Winchester Large Pistol primers are marked "For Magnum or Standard Use" meaning they do both the same just fine.

April 22, 2008, 09:40 PM
thanks for the input Evan Price. I do have Winchester Magnum primers but the box is not marked " or standard use" Just says magnum.

I use AA2 for my .357's and for .38
I have done in the past.
I am using 8 grains in my 357's, i can't find my notes but I believe I used 3.6 grains in .38's I did in the past using regular primers.

It seems to me that I would still be safe using 3.6 grains and the magnum primers but not unless I am more sure of it all.

April 22, 2008, 10:48 PM
Magnum primers have more priming compound to give faster ignition, and more consistant ignition with larger powder charges. Switching to magnums will alter the pressure curve, and the peak pressure will be reached sooner.

April 22, 2008, 11:18 PM
Any time you change components, drop the load to the starting charge and work up.

I use magnum primers in everything I load except 45 Auto and .223 Remy.

Mal H
April 22, 2008, 11:29 PM
I think this might be the most frequently asked question in reloading.

Should you substitute magnum primers for standard? No, you shouldn't. Can you? Yes, you can. Your gun won't be damaged if you drop back 10% from the load you are using (or start at the min load).

I don't think your gun will be damaged even if you don't drop back, but that is an exceptionally poor reloading practice. When you change any component (even the same weight bullet or a different brand of standard primer, etc.), you should back off a little and work up again.

If magnum primers are all you have, then that's what you use - but use them wisely. They're not bombs, they're simply hotter and more powerful than standards.

April 23, 2008, 12:16 AM

There is no rule to use standard primers in 38 spl loads and magnum primers - in 357 magnum loads. Type of primer is as much a part of the load as the amount of powder or bullet weight.

Use of magnum primers in a load that recommends standard primers will result in significantly higher pressure. This can get ugly in a hurry. I do not think that 0.1-0.2 grains of powder will always be enough to compensate. I know of at least one load where 2.5 grains does not compensate for change from standard to magnum primers!

It sounds like you are new to reloading. If you are, I recommend that you follow reloading manuals, develop your loads cautiously, and did not change components untill you get more experience.

Stay safe! :)


P.S. Mal H, just saw your post. +1. M.

April 23, 2008, 01:40 AM
Our FEARLESS LEADER... (to whom it may concern)..has thier finger on the " BIG RED BUTTON ! ) and it's primed with a winchester MAGNUM primer !!!
...seriously...back up a bit on the powder and they'll work fine...
just like these more experienced folk will tell you.

April 23, 2008, 09:30 AM
I had thought the loads I was using for these two rounds were "backed off".

I have no way to measure the speed of the bullet so I can only go by felt recoil.

The rounds I load most definitely have less felt recoil than their store bought counterparts. But they seem to fly and hit where I aim with the same consistency.

I was just looking to use the components I have on hand.

Mal H
April 23, 2008, 01:30 PM
You're fine, Im283. Use 'em and have fun with less worrying involved. ;)

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