How much of a problem is it if you use magnum primers (CCI 350s) when regular primers as called out for the load in question? The reason I ask is I have been using Winchester primers which say they can be used in either role but just bought some CCI 350's without thinking about the fact that they are specified as magnum. The book says that pressures can be higher, as much as 5000 psi, without significant velocity gains. How do the Winchester ones get away with it then?
Regular Primers vs Magnum
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Maximumbob54
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I use Winchester primers in both my .38's and my .357's but I don't load to max velocity in either one. Most of what I read and have been told is that magnum primers are needed to ignite stubborn powders that need a more uniform burn to function. This seems to be why 2400 powder makes a so so .38 but makes a great magnum. So if you are trying to push your loads to the max listed velocity you will need the right primer. So how does Win do it? My two cents says it does that good at both but best at neither kind of deal. Or at least not best at magnum max velocity listings. And I don't know about adding 5,000 psi, that sounds like just a bit much.
The CCI mag primers are for igniting harder to ignite ball magnum powders. If you are going to use them for non Magnum loads I would reduce your powder charge. Do not load any max loads and you should be OK The have more of a flame and will increase pressure so you need to compensate for that.
It also matters what cartridge you are using them in???
I would guess in a 45 ACP it makes more of a difference than in say a 45 Colt.
It also matters what cartridge you are using them in???
I would guess in a 45 ACP it makes more of a difference than in say a 45 Colt.
USSR
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The problem is not the primer when using 2400 for .38's, the problem is the powder is too slow for .38 Special pressure-level loads. 2400 is not a stubborn powder, and is easily lit with standard LP primers. In fact magnum primers are not recommended for full power .357 Magnum loads using 2400 powder.
Don
I would be using them in .44 magnum loads primarily with unique and 240gr hard cast SWC. I do have H110 and Lil'gun available along with jacketed bullets so the magnum primers will not go unused but I may try a few moderate say 8.5gr unique loads and see what occurs. Even if it does raise pressures a bit I am way down from max now. It is possible that the magnum primers may help to seal the bore and reduce leading. (Well I can hope).
ArchAngelCD
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Pressure will raise slightly with the magnum primer but i wouldn't worry at all about pressure with the charge weight and powder you're using. If you were already using Winchester LP primers you really won't see a difference in loads using a CCI LPM primer instead.
Like said above, a magnum primer isn't necessary with the powder you're using but you already know that. Not to worry in the application you're using.
Like said above, a magnum primer isn't necessary with the powder you're using but you already know that. Not to worry in the application you're using.
Hook686
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I use CCI magnum primers sometimes in my .357 and .44 magnum loads. A few years ago Alliant showed magnum primers for these loadings on their web page. The answer I got upon asking why was simply that that was what was on the bench the day they did the testing. I use jacketed 200 grain bullets.
I figure a magnum primer accounts for about .2 grains of powder. Since everyone ought start low and work up I don't see a problem. I use Winchester Large Pistol primers when loading 9.5 grains of Unique for my .44 magnum, and I use CCI Small PIstol magnum primers when I load 6.4 grains of Unique for my .357 magnum snub nose revolver. I use 158 grain jacketed bullets.
I may not need them, but if they are what I have on the bench, I use them. Have had no problems using them. Then I have had no problems when I did not use them.
I figure a magnum primer accounts for about .2 grains of powder. Since everyone ought start low and work up I don't see a problem. I use Winchester Large Pistol primers when loading 9.5 grains of Unique for my .44 magnum, and I use CCI Small PIstol magnum primers when I load 6.4 grains of Unique for my .357 magnum snub nose revolver. I use 158 grain jacketed bullets.
I may not need them, but if they are what I have on the bench, I use them. Have had no problems using them. Then I have had no problems when I did not use them.
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Hi Don,
My Lyman manual says to use only magnum primers with 2400 and doesn't mention omitting them with higher charges.
Lyman uses mag primers with all the powders used in testing as does Hodgdons load data.
Alliant does not specify using a mag primer with 2400.
Here is a interesting chart Paul posted in a thread on rifle vs pistol primers. The amount of energy is increased but IMO not that much.
In a 44 Mag load, I would not worry
Alliant does not specify using a mag primer with 2400.
Here is a interesting chart Paul posted in a thread on rifle vs pistol primers. The amount of energy is increased but IMO not that much.
In a 44 Mag load, I would not worry
John Eilertson
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When I first started reloading for my .44 mag I used Unique powder and magnum primers. After while I considered, then used, NON mag primers. My velocity lowered little, accuracy wasn't hurt and it likely did less damage to my M29. So, if you can, skip the magnum primers. My 2 cents.
USSR
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I go by what E.K. said years ago, when he was on the ground floor of developing heavy loads using 2400 powder. He clearly stated that you will get more accuracy with standard primers and 2400 than you will with magnum primers.
Don
amazingflapjack
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primers
I switched to Winchester large pistol primers about a year ago, and I like them very much. I use them in all my large caliber stuff-magnum or not. They are the only large primer that is desinated for both standard and magnum ammo. A caution I have learned is that, because they are hotter than standard primers, you have to allow for them a little when you start getting close to maximum loads. They can push you over the edge a little if you are using them in .45ACP or other large non magnum rounds. But they are great-no more un-burnt powder, and I havent had one fail to light. Go with caution. Flapjack.
I switched to Winchester large pistol primers about a year ago, and I like them very much. I use them in all my large caliber stuff-magnum or not. They are the only large primer that is desinated for both standard and magnum ammo. A caution I have learned is that, because they are hotter than standard primers, you have to allow for them a little when you start getting close to maximum loads. They can push you over the edge a little if you are using them in .45ACP or other large non magnum rounds. But they are great-no more un-burnt powder, and I havent had one fail to light. Go with caution. Flapjack.
+1. I've been loading .357, .41 and .44 Magnums for well over 30 years, all w/ 2400, all with standard primers. Reduced/low pressure loads are not appropriate for 2400.
Gotta add my 2 cents worth. I was told magnum primers add 10 fps and were not that much different from standard. That has been my experience. I use them for my cowboy loads with Trail Boss and started using them with my 9mm loads with AA #7. 
The 9mm uses a 147 grain molly bullet and the powder is 6.3 grains of AA #7. That is the bottom of the range.
I need 835 fps. 
The reason I use magnum Federal primers: They were the only thing I could get last year that were Federal!
I need to use them up.
I have a stock of standard primers now. Along with S&W revolvers and a Glock that requires them for reliability.
The 9mm uses a 147 grain molly bullet and the powder is 6.3 grains of AA #7. That is the bottom of the range.
I need 835 fps. The reason I use magnum Federal primers: They were the only thing I could get last year that were Federal!
I need to use them up.
I have a stock of standard primers now. Along with S&W revolvers and a Glock that requires them for reliability.
During the recent primer shortage, the only large Federals I could find were the magnum variety. I have used them in my much less than maximum .44 Special loads with no ill effects or noticable change in performance.
J-FRAME
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What Elmer Keith says is true by my testing. No magnum primers. Only 150 Federals and 2400 - Perfect combo for me.
What you can do is e-mail Federal and ask them what is the difference between their standard & magnum pistol primers - I think their answer will be cup thickness. A thicker primer cup with high pressure loads will greatly assist in preventing primer piercing. I don't believe there is any other difference between the Federal magnum & standard large pistol primers.
I also believe the WLP primer has the thicker cup, so it can also be used in high pressure rounds calling for a large magnum pistol primer.
The only U.S.A. manufacturer that I'm aware of that makes a "true" magnum pistol primer is CCI - their 350 is one hot puppy and your peak pressure will be higher as well.
I also believe the WLP primer has the thicker cup, so it can also be used in high pressure rounds calling for a large magnum pistol primer.
The only U.S.A. manufacturer that I'm aware of that makes a "true" magnum pistol primer is CCI - their 350 is one hot puppy and your peak pressure will be higher as well.
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