I have some 158gn SWCs I'd like to load in .357 cases for fairly light target loads to compare W231 and N340. Hodgdon's recipe calls for magnum primers, but Vihtavouri's does not. I have CCI spm, though not a bunch so if it's not necessary, I'd rather just use regular spp. I use both powders in other calibers and use standard spp but I suspect that Hodgdon's normal formula calls for magnum primers in every magnum caliber or perhaps case fill in the longer cartridge is the reason.
• Use 38Special brass, standard primers, 158gr bullets, and 4.0gr of W231. It's a fun, accurate load for 38 or 357 revolvers.
• As mentioned, generally we only use magnum primers when the powder calls for it. Many confuse "357 magnum" with the need for
magnum primers. H110/W296 does require mag primers.
• In this case, with the presence of the
cavernous 357 brass and the light load of W231, I believe Hodgdon was worried about the load becoming
"position sensitive". That's a problem created by how the powder is dispersed in a poorly filled revolver case. As the cartoon below tries to show, you can actually get different chrono readings based on whether you point the gun
up or
down before firing.
This is one reason you never hear about people using TightGroup in 38Spcl. You'll get the same effect because the "case fill" is terrible.
Anyway, Hodgdon must be using the hotter ignition capability of the magnum primer to offset poor powder dispersion inside the large volume 357M brass. So I assume the issue is the powder position, but it's definitely
not igniting the W231.
• • You can use the N340, certainly, but it's sort of a waste in plinking or practice ammo. N340 is excellent stuff and has flash suppressant. The flash suppressant means its better use is in self defense ammo. Use it in 9mm to get above 1200fps, or in 10Auto or 357M for a faster, smoother, far more accurate loads.
And N340 does
not require a magnum primer... if used with proper case fill.
