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Old November 20, 2020, 07:35 PM   #1
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Substituting mag primers for std primers during shortage.

Wondering if this is feasible during the shortage for .45ACP, 38Special, 38Super, 9mm, .380ACP. and .45 Colt.
Not there yet just looking ahead.
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Old November 20, 2020, 08:01 PM   #2
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Yes it is, but we generally download our powder charge by about .3 of a grain of powder or more, when using magnum primers over what it would be with standard primers.

Some magnum primers have a larger drop of priming compound in the primer cup and some just have a thicker cup. Some may use a mix with a higher brisance.
But we don't know who is doing what in the primer industry so we err on the side of caution and just download a little.

For the most part, they don't want to divulge their trade secrets so we just don't know.
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Old November 20, 2020, 08:11 PM   #3
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I've done it, no noticeable difference in any of my guns
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Old November 20, 2020, 11:23 PM   #4
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Substituting mag primers for std primers during shortage.

I've used mag.primers reloading 10 mm, slightly under max charge .2-.3 gr. BE86 and I found the brass comes out almost as clean after firing as when started. As usual build up a SAFE test batch maybe a 1/2 GR. light and work your way up.
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Old November 21, 2020, 01:36 AM   #5
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substitute magnum for standard primers =possible using appropriate safety precautions until you know there won't be a problem.

Substitute pistol for rifle primers = not a good idea, many potential issues.
Rifle primers for pistol = worse idea!
All else being equal (and it almost never is) bigger bullets tend to work better.
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Old November 21, 2020, 02:34 PM   #6
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Substitute magnum for standard primers might give you increased pressures.
Magnum primers have nothing to do with how much powder is used. They are about the powder, but if you change any one component you really should start over and work up the load again not just reduce by .3 of a grain. That doesn't do much of anything.
Oh and the use of magnum primers has nothing whatever to do with the cartridge name like Hodgdon's site indicates.
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Old November 21, 2020, 03:16 PM   #7
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I will find out soon, as I switch from Rem 1.5 to 5.5 soon. Of course most of what I am loading right now is cast lead powder coated low velocity training stuff, so I think I will be fine on the load, but I'll load some testers first, of course.
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Old November 21, 2020, 03:39 PM   #8
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I did some load testing in .223 with W748 testing both std and mag primers. Saw no measurable difference in consistency or accuracy, however I did notice about a 40 fps consistent increase in velocity using mag primers.
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Old November 21, 2020, 03:55 PM   #9
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Magnum primers can, indeed, affect how much powder is uses in some instances. In 223 Rem, for example, some magnum primers can cause you to bring powder charge down as much as 5% to match muzzle velocity. In the short automatic pistol cartridges, they can unseat the bullet before the powder burn starts, ironically causing you to need a larger powder charge to match a velocity. They can also cause poor ignition consistency in small powder space cases by sometimes getting the bullet out ahead of the powder burn and sometimes not. This will show up on your chronograph as increased velocity spread.

Cases are called "magnum" because they have more capacity than more standard cases in the same cartridge class do. Magnum primers are designed to make a larger quantity of gas for the starting pressure of the powder because powder needs a minimum of pressure to initiate burning and raise the pressure in a repeatable way. Indeed, too little can lead to loads squibbing out. So, recognizing larger (magnum) cases would need more gas to pressurize them for consistent burning, magnum primers were developed.

What the above fails to consider is that not all magnum cases that take the same size primer have the same case volume. lf I have a 357 Magnum case and a 32 H&R Magnum case, there isn't going to be the same need for extra starting pressure in the smaller round. So, the bottom line is, whatever the intent of the primer designer, you have to test for yourself with your powder in your cartridge to see which one better produces a desired velocity and has the most consistent ignition (usually indicated by low velocity standard deviation).

This is a worthwhile read.
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Old November 21, 2020, 04:28 PM   #10
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I in fact am starting down that path with a know good load testing directly with same powder level with magnum powder.

The load is no where near max so a possible shift would only throw me out of an accuracy node not be a danger.

The first test was interesting but not conclusive. Accuracy was almost as good, conditions for testing sucked (20 deg, a bit of wind). I was so excited to go shooting (well that changed) I forgot to get my insulated pants on (yes I did have pants)

The non magnum group was a gorgeous 1/4 inch in 5 shots. 1/2 inch with all 5 (still not bad and close to the 3/8 this load delivers when I do)

The magnum was also a 1/4 x 4 and then a wilder one for 5 shots at 3/4 inch.

As I and my hands were freezing at that point I gave up and will resume the tests next week when its warmer or I dress up right.
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Old Yesterday, 10:10 AM   #11
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downloaded 40s&w aa#5 from 6.5 to 6.4, switched to ccimag spp. no change. started at 6.1 grains, worked back up. burns noticeably cleaner imho. no burnt flakes like before.

h335 is a ball powder which likes a mag primer. in fact, i think speer data has 223 with mag primer.
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