Primer types

[Micro man]

Currently vacationing in Northern Michigan away from my reloading manuals, I decided to visit a large sporting goods store in the area(Jays) in my current search for reloading supplies. I found a large variety of powder and picked up a couple pounds. They also had some large pistol primers of which I bought 400.
Also available were large magnum pistol primers which got me wondering what you use them for.
Any enlightenment would be appreciated.

[nhyrum]

Originally Posted by Micro man

Currently vacationing in Northern Michigan away from my reloading manuals, I decided to visit a large sporting goods store in the area(Jays) in my current search for reloading supplies. I found a large variety of powder and picked up a couple pounds. They also had some large pistol primers of which I bought 400.

Also available were large magnum pistol primers which got me wondering what you use them for.

Any enlightenment would be appreciated.

I use large Magnum pistol in my 9x25 Dillon. It's a 10mm auto necked to 9mm. Loaded with h110, which just prefers Magnum from what I hear. It's a lot of powder(almost 20 grains). Anyway, from what I hear h110 is just a bit tough to light well so I use magnums. Since I shoot it so much I use the same primers in my 45 Colt. The only gun I have that shoots 45 Colt is a 454 casull, so I'm not worried about pressure.

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[Aguila Blanca]

.44 Magnum and the like.

[44 AMP]

Magnum primers are recommended for "difficult to ignite" powders (usually the slow ones) in larger volume cases.

The are often recommended for use with ball powders.

The priming compound mix is either more, or hotter than standard primers, depending on who makes them.

Winchester doesn't have a magnum pistol primer, their primers are listed as "for standard or magnum loads".

CCI, Rem and others do have magnum primers rifle and pistol in both sizes.

I load Unique in .45 Colt and use standard primers. Loading 2400 or H110 in .44MAG or .357 Mag I use magnum primers. Won't say it is a necessity, but will say it absolutely works well.

[gwpercle]

Best used when the load data calls for them .
Some slow burning powders , especially ball type powders in large charges need a magnum primer to get consistent ignition .
They are used when the powder needs needs them . Just because the cartridge is called 357 magnum , 41 magnum , 44 magnum ...etc. you don't have to use magnum primers, in fact , most loads use standard primers .
And don't go substituting magnum primers for standard primers in loads you have worked up ... this could get you in hot water if not done with care and caution !
Gary

[Kevin Rohrer]

Magnum primers are used w/ H110 powder.

[Unclenick]

In general, for any primer type, magnum primers make a larger quantity of gas to pressurize the case adequately to achieve consistent powder ignition timing. As a result, they are used in larger capacity cases or in medium capacity cases when the load density leaves a lot of unfilled space in the case and so needs more gas to reach the burn starting pressure. In rifle, it is not uncommon for magnum primers to produce the best accuracy and lowest velocity variation with charges that don't fill the case well, but for a standard primer to do better when a charge of the same powder fills the case enough. Some powders, particularly those with heavy deterrent coatings, can require extra starting pressure.

In addition, most domestic primers these days throw a shower of white-hot burning metal particles to help with starting through heavy deterrent coatings. The addition of metal dust appears to have begun in earnest with CCI magnum primers in 1989, when they reformulated them for the older St. Marks spherical powder formulations. Today the same spark shower is produced by many standard primers. As a result, in some instances, especially in shorter pistol cases, the standard primers ignite those slower, high deterrent powders just fine. Some of the primers from Europe and the former Eastern Bloc countries do not make the spark shower. The bottom line is you have to test with the primer you want to use to see what it does.

[Micro man]

Thanks for the education, makes sense now!

[cdoc42]

I use small pistol mag primers with 2400 in .357 Mag. Is there any reason not to use them in .38 Special with Unique, or 9mm with Titegroup, HP-38 or CFE Pistol?

[jimbob86]

I use small pistol mag primers with 2400 in .357 Mag.

I suggest you do a side by side comparison ....... I got better velocity and smaller SD with standard small pistol primers than with magnum in my 2400
158 gr .357 loads ..... H110 NEEDS a magnum primer.

[Unclenick]

That can happen because the primer can start unseating the bullet before the powder gets burning well, so the effect is like seating the bullet out further.

[Average Joe]

I have used small pistol magnum primers in standard loads without any problems in a pinch. My supplier sells them at the same price as regular primers, so I have started to use them more often for regular loads.