Primer Problem

[Ronvandyn]

OK, so I have this little problem. 

When I went to Cabela's a few weeks ago I bought primers, and didnt notice that they were Magnum primers.  So I have loaded quite a few of them up, even shot a few without problem, but today I actually noticed that they were not regular primers but magnum.

I'm loading 45acp (large primer), 40 S&W, and 380acp.  I am not loading anywhere near max load for any of them, just target loads. 

Question:  How much more powerful are magnum primers over regular one's and will this cause problems? 

Obviously I feel like a complete dope for not noticing, but I'm still new to this whole reloading thing and am (I hope) making the usual mistakes.

Ron
 

[Dan W]

Ron, I have read many posts online that suggest your mid range target loads will not be a problem with magnum primers, and I have seen others recommending a .1 -.2 grain reduction in powder when using magnum primers. That is often within the deviation of a good powder measure, so I would not fret too much over it.

If I was worried at all it would be the .40 cal loads.

If you can chronograph them, that would be the evidence you need to allay all fears of an overload

[RLMoeller]

Magnum primers are designed to burn longer and hotter for large capacities and for powders that are more difficult to ignite.  You could end up with increased chamber pressures when using a magnum primer where it isn't intended.

Because you say you are not anywhere near maximum charge you are probably OK.  But it would be best to treat these like any new component and start light and work your way up, like you would when you try a new powder.  No guarantee though.  The safest solution is to start using the right primers.  (and purchase something chambered in a caliber that requires magnum primers) 

As to your specific question, I don't know how to quantify "how much more powerful".  CCI claims their magnum primers are 23% hotter.  I don't know how to equate that to an increase in chamber pressure as that would vary by a number of factors.

[Rich B]

As RLM stated, you are probably OK. 

I used magnum primers in some 9mm loads using medium charges of Power Pistol and notice no differences in my brass or in felt recoil.

But, like I said, I was using medium charges.  If you're pushing the envelope, work up carefully. 

[Ronvandyn]

Thanks guys.

Currently all my target loads except the .380 run anywhere from 1 to 2 grains below max load (not .1 or .2, but a full 1 or 2).  The 380 is just so dang small that dropping a full grain could also present a problem, so I am running those .5 to .8 grains lower than max.  So far there have not been any problems with either firing or the cases bulging.  But being new to this portion of the hobby I knew I had made a mistake, just not how big of one.   Good to hear that its not as drastic as I feared.

Besides, I'd hate to have to pull close to 500 rounds apart because of this. 

Ron

[unfy]

I'm glad to see that it's not a catastrophic mistake.  Does offer some peace of mind for me, and I wanted to thank the responders for their responses.

I would have disassembled the rounds myself. Things like that scare the hell out of me. Granted, I fire higher pressure cartridges (ie: the before mentioned .40), so... I tend to be more finicky. 

Also - if you're using those 500 rounds for just completely informal shooting, you're prolly alright.  Changing back to regular primers will change the performance of the recipe, so you'll probably notice changes in accuracy (which reloading are all about consistency).