This may have been answered at some point . My Speer Manual number 8 calls for magnum primers when loading .357 Mag rounds. I have some Winchester small pistol magnum primers but this is the only book that calls for this primer. I use 2400 in a lot of my .357 loads. Are there some powders that work better with a magnum primer?
Magnum primers?
- Thread starter jhde69
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Yes, WW296 & H110, which are the same powders, just in different packages. Alliant recommends using std primers with 2400. I always check the powder manufacturers recommendations when selecting primers. The results can be surprising.
Two of the magnum powerhouse powders that require mag primers are WW296/H110[same animal but different exterior packaging].
H110/W 296 require Mag primers.
2400 Does not.
Some use Mag primers for HS 6
Now for large pistol Winchester primers are for both Regular and Magnum.
You will see that any Mag load data that has Magnum that Hodgdon posts, uses a Mag primer. Not that it is needed, just to be constant. (I called them and asked about it)
Alliant does not say use a Mag primer with 2400.
Alliant Powder - Reloader's Guide
You can see by this chart that a SPM has a bit more energy than a regular. So I would not be afraid to use them, just not with a max powder load.
2400 Does not.
Some use Mag primers for HS 6
Now for large pistol Winchester primers are for both Regular and Magnum.
You will see that any Mag load data that has Magnum that Hodgdon posts, uses a Mag primer. Not that it is needed, just to be constant. (I called them and asked about it)
Alliant does not say use a Mag primer with 2400.
Alliant Powder - Reloader's Guide
You can see by this chart that a SPM has a bit more energy than a regular. So I would not be afraid to use them, just not with a max powder load.
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Speer Manual #8 is probably at least forty years old. Testing methods, powders, primers, etc. may have changed a bit since #8 was published. Might be best to consult current manuals, though many handloaders consider mag primers only necessary for Win 296 / H110. Most published loading data indicates this.
Using a 6" Python .357, I actually got slightly (very slightly) better accuracy with with magnum primers vs. standard (both CCI) with #2400 powder and a 158 grain cast bullet. However, the difference was not great enough to make me want to stock a different primer.
Accuarcy with 296 is equal to #2400, but muzzle flash and blast is noticeably greater, both in the .357 and the .44 Magnum. Because of this, I seldom use 296 anymore.
Using a 6" Python .357, I actually got slightly (very slightly) better accuracy with with magnum primers vs. standard (both CCI) with #2400 powder and a 158 grain cast bullet. However, the difference was not great enough to make me want to stock a different primer.
Accuarcy with 296 is equal to #2400, but muzzle flash and blast is noticeably greater, both in the .357 and the .44 Magnum. Because of this, I seldom use 296 anymore.
