Using Magnum Large Pistol Primers in Non Magnum Cartridges

L

lwestatbus

New member
I have 300 older Federal Large Pistol Magnum primers (No 155). Primers and packaging are in excellent condition. I would like to use these but none of my large pistol loads call for magnum primers. I'm wondering if there is a downside to using these in my three cartridges that take large pistol primers. These are:

  1. .44 Magnum w/ 21.5 grains of IMR 4227 w/ 240 gr jacketed bullet
  2. .44 Special w/ 4.5 gr TiteGroup shooting 240 gr jacketed and plated bullets
  3. .45 ACP w/ 4.8 gr of TiteGroup shooting 230 gr plated bullets

Again, none of the recipes call for magnum primers.

I've browsed posts in the Forum and see issues such as too-large primers unseating bullets prematurely and also opinions that magnums will do no harm. I've even seen suggestions to use small rifle primers in some cases. :confused: Because the TiteGroup loads take up a tiny portion of the cartridge case I could see not wanting to overpower these with a magnum primer.

As always, thoughts will be welcome.
 
This is a very, very common question. There are a slew of different answers but I genuinely feel there is one BEST answer:

—you can always use a magnum primer in ANY cartridge*, but it’s foolish and possibly reckless to simply stick a new primer in to any handload you’ve already developed if it’s anywhere near max. It’s also foolish to switch a primer and expect no change.

Instead — lower your charge weight and develop the load again.

*one place you might have an issue with a magnum primer is any exceptionally tuned action where your firing pin/hammer makes a light hit. For me, this is in tuned double action revolvers. Magnum primers typically have a thicker, harder primer cup and they will resist being hit.
 
Again, none of the recipes call for magnum primers.
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This is also something I tend to disagree with — and I’m sure others may disagree with my take.

You say the “recipe does not call for them” but I argue with what we are actually seeing with published load data.

It’s my position that it’s not a strict recipe. I say it is a detailed guideline and more to the point — published load data is a detailed test result that you could never possibly replicate completely.

They show you exactly what components they used and they do this because they did an experiment and these details matter. You can never exactly replicate what they’ve published because you cannot hope to do everything exactly as they did.

You don’t have their brass, you don’t have their chamber dimensions or their throat. You might find yourself with a similar ambient temperature, but will you be at the same elevation and with the same barrel length and are you using the same brass?

I think too many get wrapped around the axle when it comes to published data. There is a lot of room for interpretation and I believe we benefit from it when we know and accept this.
 
The magnum primers are most applicable to the 44 magnum load. To be safe, drop that load back to 20 gr. of 4227 using the hotter primer. Unless you are intending to do some long range shooting, the slightly lower velocity will not be noticed, and they may be more accurate, anyway.
 
Using magnum primers in smaller, or low pressure cases with fast burning powder is simply a waste of the magnum primer's purpose.

Find someone who shoot loads which need a magnum primer and trade them or sell them to someone who needs them. Pretty sure there's someone local to you shooting H110 or W296 or some other slow powder who will be happy to get them.
 
Jim, I didn't have a reloading manual in front of me, but 20.0 gr of 4227 is still a powerful load, and there's no such thing as too safe.
 
I got some mag primers during Covid as they were the only ones available. I tested them against non mag primers in my low power Bullseye loads and saw no difference in fps at all. That in 45acp.
 
Used magnum primer in non-magnum loads in the past with no ill affect. No signs of over pressure and no noticeable increase in FPS but there was a slight decrease in SD.
 
I have gotten back into shooting pistols, BP mostly due to the long sight distance I can see ok with an EyPal aid.

So, looking at my stuff from lo many years ago and I have a brick of Magnum LP primers and a couple hundred regular. I just ran the loads up using the Magnum Primers. Works fine.

Would I buy Magnum primers for the 45 LC Cowboy type loads? No, but like my Speer Bullets in the 41 magnum, I am going to use them up.

Now if I had a load up at the high end, I would not replace a Regular Primer with a magnum. As others have noted, drop the load down and then move up if you want.

For me I just want target loads, big bang not needed so something in the 850 fps area and then see if a bit more speed makes any difference.

By the way, for lower loads, Unique has proven to be the best so for. That is in 45 LC with lead Semi Wadcutter as well as the 41 magnum with the JSWC.

The 47 Walker with a Conversion Cylinder in 45LC at 850 fps is a bit like shooting a 22. That is one heavy beast of a gun (and yes I am resting it).
 
I’d try them with the 4227, although my experience with 4227 has been limited to only one pound I’ve found with standard primers it tends to leave unburned kernels in the bore. Accuracy was excellent, MV kind of so so. I switched to 2400 due to better performance and no unburned powder left in the bore. Obviously work your load up from the start.
 
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