Large Pistol Primers ......

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Odinson

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Just wondering, anyone using large pistol primers in place of large rifle? I have some Winchester large pistol that say for standard and magnum loads. Thinking of trying a few in 303. Not going to go beyond "starting" loads. I figure 3031 powder and 174 gr bullet.
Comments???
 
Not a recommendation however I get ok results with large pistol magnum primers in smokeless .45-70 Marlin reduced loads for example.
 
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I measured both and the pistol primer is about .010" thinner so I figure it will sit a bit deeper in the primer pocket.
 
Got the idea from an article in Handloader's Digest 13th ed. author states CCI 350's worked fine for him softer/thinner primer cups showed variation in appearance across his .45-70 Marlin handloads pressure range whereas large rifle primers didn't.
 
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IIRC, there is also a difference in the height of the primers, with the large rifle being a bit ( 0.004" ? ) taller.
For low pressure loads, I wouldn't hesitate trying a few LP in rifle cartridges, but no way would I try one in a 338 RUM....
 
It would be tempting. But consider this. The cup height / primer pocket depth of LP primers is shorter than LR. And most .303 rifles I have had experience with have had some headspace issues. Chambers are often sloppy. And the metal in LP primer cups is thinner. Combine a too - deep primer with a sloppy chamber/long headspace, and misfires, or partially backed out primers / firing pin piercing & gas leaks may result. You already know about the thin cups and limits of pressures. If you're asking for advice, I wouldn't suggest you do it.
 
I have used LP primers in loads for the 30-30 and 38-55 in the past without issues.
But both are relatively low pressure chamberings, so take that for what it is worth.
Dave.
 
⚠️ Pressure considerations -

.44 Rem Mag rifle/pistol for example 36,000 psi max pressure uses LP magnum primers.

.500 S&W Mag pistol/rifle 60,000 psi max pressure uses LR primers.

Plus possible rifle heavier firing pin strike could pierce LP primers? Not a pleasant event. ⚠️

Sierra: "In summary, do not substitute LPP for LRP at all, period."
https://www.sierrabullets.com/primer-substitutions/
 
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If you are going to use LP primers for rifle cartridges make sure you always wear shooting gloves and a good set of safety glasses.
 
OldDude said:
IIRC, there is also a difference in the height of the primers, with the large rifle being a bit ( 0.004" ? ) taller.
For low pressure loads, I wouldn't hesitate trying a few LP in rifle cartridges, but no way would I try one in a 338 RUM....
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I measured both and found a 0.010" difference. Folks say that the pistol primer is thinner but I have no way of measuring.
 
Well, I loaded 9 rounds of 303. Large Pistol Primers, 32 grains of 3031 and 174 grain Hornady 174 grain hard point boat tail. I'll try them in a week or so at the range.
If I don't post results, you will know that the experiment failed.
 
All LP primer cups are 0.025" thick with varying hardness. All LP primer cups are 0.027" thick with varying hardness, LR are taller by .010" or so. The pressure limit I have seen often quoted for LP primers is 45,000psi but where that number came from, I cannot say.

I have used LP while fireforming cases. Some rifles will pierce the cup but I think it's more to do with an overly aggressive strike compared to pressure causing the cup to blank or otherwise fail.
 
Got .350 RM loads at cast bullet level to test with Ginex LP magnum primers. Remember not recommended don't try this at home. Or wherever else.
 
Odinson said:
Just wondering, anyone using large pistol primers in place of large rifle? I have some Winchester large pistol that say for standard and magnum loads. Thinking of trying a few in 303. Not going to go beyond "starting" loads. I figure 3031 powder and 174 gr bullet.
Comments???
Click to expand...

If you get a pierced primer it will blast chunks out of your bolt face, not a good idea.
 
I use LP in some black powder rifle cartridges but i wouldn't use them for smokeless cartridges that generatemore pressure than the pistol rounds they were meant for.
30k psi is probably fine. 60k psi is a condition they are not designed for.
 
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