reducing powder w/mag primers
Like many people I have acquired a number of magnum primers over the years. With cost/availability issues on primers I would like to use these up. Is there a general rule of thumb for reducing powder charges when using magnum vs standard primers? thanks Don
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THIS IS WHAT I DO, you may feel different.
I don't worry about the substitution when the loads I am using are middle of the book. I just load the magnum primers and go shoot. It is a different story when seeking maximum accuracy. Pistol loads are not treated any different as long as the load is middle of the road. If it is book max I drop back a bit, working back up, looking for signs of pressure.
There was a recent post about this issue by Rocky Rabb you may want to do a search for it and read the article he wrote. He has a good system worked out for those concerned about it.0 -
+1 on using the primers as normal! I was calling tech support at Dillon and while I was on the phone I asked about the extra magnum I had on hand and they said that there is such a small difference and go ahead and use them.
Emmett0 -
+1 on what was already stated. 0 -
Hi,
I think the information given thus far has been accurate. You didn't indicate if you would be using them in a rifle or pistol or both.
I would use some degree of caution on substituting magnum primers in the 45 ACP. I substituted magnum primers in the 45 ACP and was shooting a light to middle range charge of powder. The combination was incorrect, or was at least incorrect for the combination of components being used and my pistol, which was a Kimber Gold Match. The load was hot enough to partially back the primers out of the pocket or else to blow the primers completely out of the pocket. This was with a target load that shot with no obvious effect from the same pistol, all other components the same except for the primer. I experimented briefly with changing the charge of powder, but the result was always the same. I switched back to regular primers and the problem disappeared.
It may be that cases of limited capacity, such as the 45 ACP, are not capable of handling any additional pressure from a magnum primer even with a light to middle to charge of powder. I am not saying this would happen to everyone, but approach with caution.
Regards,
Heavyiron0 -
FWIW,
I did some chronograph studies with my .44 mag. a few years ago.
Using hard cast 240 SWC, I got essentially identical velocity and accuracy with 21 grains of 2400 and CCI 350 as with 22/ and CCI 300.
v35, Are you suggesting that the 21 grains may be a too light, detonation inducing load? Keith's load of 22 grains was the standard for years, though most who quote it, including Keith, rarely mentioned the primer used. I've always associated detonation more with slow burning powders in large capacity rifle rounds; not near max. loads in handguns. I've never heard 21 grains of 2400 in the mag. case referred to as a light load, but then in many ways I'm living back in the '60's anyway. I'm willing to be educated.
Ambrose and v35, I recall seeing the same article. It just always bugs me a bit when writers quote loads, especially warmer ones, and don't specifiy the primer used. Happens a lot, though not as much as it used to.
As for the case capacity on the .44, I finally got around to confirming my recollection about the 21 grains of 2400 load. In my brass, Norma full length .44 Mag., 21 grains of 2400 comes to about .4 inches from the top. The 240 grain hard cast SWC that I shoot measure, from base to crimping groove, .4 inches. In other words, 100% of available air space taken up with powder. Keith's 22 grains would be ever so slightly compressed. Not sure where the 85% figure would come from??0 -
I question if detonation may be going on when cases are filled to very low percent capacity and magnum primers are used.
The 44 mag cases with 21 gr 2400 powder may fill cases to about 85%(est) capacity. They will take a few more grains of 2400.
I was estimating with 85%. Probably if you settled the load you would see some airspace.
You misread me.
The point is, the best loads fill cases or pretty much so.
I was suggesting a few grains of bullseye or unique in a 45ACP case doesn't.
It is in these instances a magnum primer may be dangerous.0 -
RCrosby: In one of the articles about Keith that I read some time ago, it was mentioned that Keith said he did not use magnum pistol primers. 0 -
martinicadet
I will be the disenting voice here apparently. I've been reloading for about 45 years, with nary a problem. But, I never vary from the published data by a reputable manufacturer. Sure, their data is conservative, and sure you can get away with a lot of fiddeling around on your part. Just remember that it is your pretty face behind that gun. (Your post doesn't indicate what cal. you are referring to). Just remember NO. 2---STUPID HURTS--- HAWKSHAW0
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