Careless Mistake


May 26, 2013, 12:17 AM
I was about to load up some .38 JHP today and I had just cleaned a large batch of brass. I already had 93 cases primed and ready to load, so I topped it off with 7 more. After I did I noticed I had foolishly used magnum primers on those 7.:banghead: They are all the same headstamp and I had already threw them in a container with the others so I can't pick them out. I don't want to deprime them all but I will if necessary. Of course now I don't plan to load anything even remotely close to max with them, but how concerned should I be about over pressure? I am hoping I can just load up some mouse fart wadcutter loads or something with them, but I wanted to ask here first. Any help will be greatly appreciated.

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May 26, 2013, 01:31 AM
If you are loading at a start load of whatever powder, I would not worry about it. The Mag primers are hotter but with the min powder charge should not be a problem.

May 26, 2013, 02:06 AM
It shouldn't be a problem as long as your not loading to max. I doubt that you will even know the difference when shooting them.

May 26, 2013, 02:24 AM
38spl is such a low pressure round that I wouldnt even be worried unless you are shooting some hot 38+p+ rounds out of a 38 not rated for +p.

May 26, 2013, 10:37 AM
Agree with all the rest. When magnum primers where all I could find I used them with no issues in my .38sp

May 26, 2013, 12:28 PM
GG, Shoot them. Below max loads, there's hardly any danger in my opinion, however, I'd shoot them together along side 7 with regular primers and see if there is a difference in POI. Might be useful information.

May 26, 2013, 12:48 PM
Load them and shoot them up in a .357.

May 26, 2013, 01:00 PM
I have been using mag primers on all my 9mm .38 and .357. Really haven't noticed any change on charge weights between standard and magnum primers. Using all the same load data I did for standard pistol primers. I did start low and work my way back up when I switched primers though.

May 26, 2013, 01:49 PM
Thank you everyone for your help. It is much appreciated.

May 26, 2013, 01:49 PM
I agree with what has been said. It really should make very little difference. If I were in your situation I would carry on as normal. I doubt you would notice any difference and am confident that this isn't a dangerous situation. I have used magnum primers in place of regular primers in many different handgun loads and have never noticed a difference. So much so, I have begun to question the usefulness of magnum primers. I have read the literature and accept they are hotter but have never experienced anything to convince me of that first hand.

May 26, 2013, 01:50 PM
When the "Shortage" of components started in '08-09', I started using what I could find. Magnum primers will work fine-you probably will not notice any difference..Heck, on some mag. loads, I have even used Rifle primers--works for me...Bill.:)

Hondo 60
May 26, 2013, 09:26 PM
It shouldn't be a problem as long as your not loading to max. I doubt that you will even know the difference when shooting them.

Yup, agree totally!

May 26, 2013, 09:56 PM
I wouldn't overly concerned. I've actually run out of standard SP in the middle of a session, and substituted with mag SP with +P data. I didn't see any serious increase in fps through the chrony, but there was some increase. But nothing bad happened, and I didn't encounter any signs of high pressures either. But I was using a .357 mag firearm, so I was not uncomfortable about using them.

So in my experience, they do make a difference, just not a serious difference.


May 27, 2013, 01:12 AM
Its not a big deal. Even if you were loading near max, realistically it wouldnt be a big deal. We stress safety here so the advice would be to not shoot a max load, but in experience, its not a problem.

I have NEVER seen a gun blown up because someone used a magnum primer in place of a standard. Not once. Not even suggested.

May 27, 2013, 02:31 AM
The difference between standard and magnum primers is not measured by which one is hotter, but by which one has more “brisance” or shattering capability.


Brisance is the shattering capability of a high explosive, determined mainly by its detonation pressure. The term originates from the French verb "briser", which means to break or shatter. Brisance is of practical importance for determining the effectiveness of an explosion in fragmenting shells, bomb casings, grenades, structures, and the like.

Fragmentation occurs by the action of the transmitted shock wave, the strength of which depends on the detonation pressure of the explosive. Generally, the higher this pressure, the finer the fragments generated. High detonation pressure correlates with high detonation velocity, the speed at which the detonation wave propagates through the explosive, but not necessarily with the explosive's total energy (or work capacity), some of which may be released after passage of the detonation wave. A more brisant explosive, therefore, projects smaller fragments but not necessarily at a higher velocity than a less brisant one.

The sand crush test is commonly used to determine the relative brisance in comparison to TNT (which is considered a standard reference for many purposes). No single test is capable of directly comparing the explosive properties of two or more compounds;[citation needed] it is important to examine the data from several such tests[citation needed] (sand crush, trauzl lead block test, and so forth) in order to gauge relative brisance. True values for comparison require field experiments.[citation needed]

I can’t comment as to the efficacy of the magnum primer over the standard primer. Perhaps someone with experience could chime in here.

May 27, 2013, 06:35 AM
A little while ago I wondered the same thing. Primer availability being what it is. So I loaded up a few 45acp's. Using Win NT cases I tried small pistol, small pistol mag, and small rifle primers. With a mid range load shooting at ten yards offhand I could not tell which was which. They all shot point of aim. They were all fine. I'm not sure I would try this with a maxed out 40 but with a 45 no problem. A 38 should be equally as forgiving.

May 27, 2013, 07:21 AM
Been doing it for years. Never had any problems whatsoever.

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