Beating The Primer Dead Horse

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GJeffB

New member
I've been around, just lurking. Suddenly a question, just to confirm.
I think I have this, but multiple checking here and elsewhere:

Reloading .45 Colt. Mid-range charges (7.5+/-) of Universal, 255gr Keith SWC and 250gr coated RNFP in the NM Blackhawk. CCI 300 LP primers. The primers are getting harder to find.
Q: In a pinch, I can use LP Magnum (various manufacturers), back the load down by 10-ish% and re-work watching for the pressure signs. <--- Is that a correct statement?

-jb, ready to use sparklers :mad:
 
Jeff as long as you work your load back up you should be good using magnum primers. You could even use small rifle primers if you had them (they’re probably harder to come by than small pistol), so long as your revolver would set them off. The primer cup is usually harder in SR primers to withstand higher pressures of rifle rounds, and hence some pistols don’t have the hammer force on the firing pin to set them off. As long as you back off and work back up you will be good.
 
From std to magnum only requires about a 2% reduction for rework.
A 10% change (which is what going from max load to start load) is required to cover the whole gamut of bullet, primer, and powder lot number change.
 
. You could even use small rifle primers if you had them
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Only if the OP has .45 Colt brass with small primer pockets. I've never seen any like that, but I suppose it is possible these days....

Large pistol magnum primers should work fine. Everyone's primer is a little different, Testing has shown some magnum primers raise pressure as much as 15%, (in some loads) others do not. Drop your load the same as you would when changing any other component and work back up as usual.

Note that Winchester doesn't make a "magnum" primer, they make a primer "for standard and magnum loads".
 
Only if the OP has .45 Colt brass with small primer pockets. I've never seen any like that, but I suppose it is possible these days....
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Good catch, and my bad. I had stupid attack there. I wonder about LR primers in place of LP primers. I’ve heard of substituting SR for SP, not with large primers though.
 
Thanks for the replies, people. I appreciate the confirmation. It's getting so I have to improvise more and more.
Whiskey, I figured 'twas a typo. I had a similar thought about LRPs. I'd bet the Blackhawk would touch them off, I'm just not willing mess with them that much ... yet :rolleyes:

-jb
 
You might find Large Rifle Primers to be too "tall" to fit in the pistol brass primer pockets. Some might work, others might not. I wouldn't try them if there were any alternative.
 
Unlike small primers, for which pistol and rifle are the same height, with large primers the rifle primer mid-tolerance range height is 0.009" taller than for pistol primers. That may not seem like much, but when you consider optimally seated primer will typically be between -0.002" and -0.004" below flush with the case head, you can see it is enough to force the primer to seat proud of the pocket, which is a recipe for slamfires in some guns and jams in others.
 
Unclenick:
... enough to force the primer to seat proud of the pocket, which is a recipe for slamfires in some guns and jams in others.
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Would probably fail my wobble test (standing loaded round primer down on flat surface and check for a wobble) as well.

-jb
 
Here is the difference in one .45 Colt load (from one of my back to back tests):

5 1/2" Ruger BH
8.0g Universal Clays, 250g RNFP, CCI-300, 894fps, 13 SD, 44 ES, 13 shots
8.0g Universal Clays, 250g RNFP, CCI-350, 935fps, 27 SD, 88 ES, 13 shots

You'll have no worries with substituting Magnum primer with this powder. May not be as accurate is all.
 
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It's not that predictable. There have been some loads for which no difference can be detected, so for which the magnum produced better accuracy and lower ES and SD and some completely the opposite of all than and lower velocity to boot. Part of the reason is that what makes a magnum primer different from a standard one is that it produces more gas to raise the burn starting pressure in a larger (magnum) case. But there are different approaches to doing that. Some makers just increase the amount of their same priming mix in the magnum primer. Others add only fuel compounds and non-sensitive oxidizers which makes the extra gas but lowers the brisance. Some just change the temperature with metals to make hotter sparks. Some magnum primers have heavier cups so it takes higher firing pin energy to get the same ignition behavior out of them that a thinner cup would produce. So all sorts of things can happen.

The biggest difference in velocity I've read about was in a 2006 Handloader Magazine test article by Charles Petty of small rifle primers in a 223 Rem with 24 grains of RL 10X and 55-grain Hornady V-max bullets. The mildest primer (Fed 205) shot about 3150 fps from his 24" barrel. The hottest one, a CCI BR-4, IIRC, got 3300 fps. It was the equivalent of about 5% increase in powder charge. So I always back the load down at least 5% for a primer change.
 
If your recipe is not at the maximum recommended load, let's say you are 10% below to start with, would you have to reduce that when trying a magnum primer?
 
If your recipe is not at the maximum recommended load, let's say you are 10% below to start with, would you have to reduce that when trying a magnum primer?
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I always switch primers out like nothing on my standard loads that are well under max pressure, without making any changes. My warmer loads, I back off a bit.
 
GJeffB said:
I've been around, just lurking. Suddenly a question, just to confirm.

Reloading .45 Colt. Mid-range charges (7.5+/-) of Universal, 255gr Keith SWC and 250gr coated RNFP in the NM Blackhawk. CCI 300 LP primers. The primers are getting harder to find.
Q: In a pinch, I can use LP Magnum (various manufacturers), back the load down by 10-ish% and re-work watching for the pressure signs. <--- Is that a correct statement?
Click to expand...

Of course you can use a Magnum primer and there's no need to back-off the load.

Most reloading manuals list two categories of .45 Colt loads. The first category contains loads within the 14,000 psi ... SAAMI maximum pressure limit. These loads are safe in all modern .45 Long Colt revolvers.
The second .45 Colt section contains loads intended for use only in stronger revolvers like the Ruger Blackhawk, T/C Contender and Freedom Arms which can easily handle 25,000 psi
Since you'll be using a New Model Blackhawk, magnum primers are of little concern.
 
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