Just started prepping some once fired Federal brass 10mm Auto cases. The factory boxes appear to be the same ammo, but two different boxes use different primers. One box is small primers, the other one is large primers. The question is: would I be best to use Small Magnum Pistol primers in the cases that have the small primer pockets? And how common is it to find factory ammo with two different primer sizes for the same caliber?
10mm Auto Primers
- Thread starter CaribooBC
- Start date
I found the same issue with my 10mm auto. I use regular LP in the large pistol primer cases and regular SP in the small pistol primer cases. I don't load anywhere near the max as I find the recoil excessive. My memory says that the manuals I checked only mention the large pistol primers.
I could see me trying small pistol magnum if I'm using a slower powder like Blue Dot and, again, not loading near the max charge.
I find the same thing with 45 ACP. Given the choice I use the large pistol primer cases, especially when I get my cases back. For some matches they are "lost brass" matches so I generally use the small pistol primer cases. Depending on the powder, I sometimes use SPP or SPM primers. I posted a thread about that a while ago, listing powders I had problems with.
YMMV - I'm just a random guy on the internet....
I could see me trying small pistol magnum if I'm using a slower powder like Blue Dot and, again, not loading near the max charge.
I find the same thing with 45 ACP. Given the choice I use the large pistol primer cases, especially when I get my cases back. For some matches they are "lost brass" matches so I generally use the small pistol primer cases. Depending on the powder, I sometimes use SPP or SPM primers. I posted a thread about that a while ago, listing powders I had problems with.
YMMV - I'm just a random guy on the internet....
OP,
Federal,Speer,Blaser Brass 10mmAuto, depending on vintage will have large & small primer pockets.
CCI Blazer & CCI Independent are of non reloadable aluminum cases w/ berdan primers.
Other manufacturer 10mm Auto brass will have large primer pockets.
Magnum primers are not required to ignite <15 grains of smokeless powder.
Federal,Speer,Blaser Brass 10mmAuto, depending on vintage will have large & small primer pockets.
CCI Blazer & CCI Independent are of non reloadable aluminum cases w/ berdan primers.
Other manufacturer 10mm Auto brass will have large primer pockets.
Magnum primers are not required to ignite <15 grains of smokeless powder.
I have considered the LP primer to be a bit of a bad thing. It's really not necessary and such aggressive ignition can work against you with some powders. Even when considering SP there just isn't any need for a magnum primer. All the usual 10mm powders are plenty fast enough to do fine, or possibly better, with a standard primer.
BattleRife
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This has been common with .45 Auto for several years now, as some makers transition some or all of their lineup to small primers, from the traditional large.
This is the first time I have heard 10mm Auto is undergoing a similar change. I'm not aware of any other.
The primer should match the powder and the load. A midpower charge of Unique or 2400 works well with standard primers.
A full charge of H110 or 296 needs a magnum primer for reliable ignition and to withstand the pressures.
A mid power charge of a ball powder will ignite much better with a magnum primer. A ball powder is sensitive to how full the case is, so a milder charge is harder to ignite. A firm crimp will aid good ignition.
A full charge of H110 or 296 needs a magnum primer for reliable ignition and to withstand the pressures.
A mid power charge of a ball powder will ignite much better with a magnum primer. A ball powder is sensitive to how full the case is, so a milder charge is harder to ignite. A firm crimp will aid good ignition.
That would be great advice if we were talking .357 Magnum. 10mm powders are significantly faster, for instance H110 is just too slow and 2400 is a pretty terrible choice, at least it was in my testing. The slowest 10mm ball powder I can think of is AA9, which is plenty fast at any charge weight to do fine without a Magnum primer. I have always wanted SP primer 10mm brass, it's too bad I have pails of LP and zero SP.
