Magnum primers in LEE modern reloading

In Modern Reloading #2 (by Lee), the narrative portion of the manual says to NEVER use magnum primers unless load data specifically calls for them. WELL, none of the load data in that manual calls for them (not even MAGNUM loads).
So, the simple question: Do I use small magnum pistol primers for the .357 magnum data in Lee's Modern Reloading?

Magnum primers are not necessarly used just because the cartridge name says magnum on it.
That has nothing to do with anything.

If you use ball or sperical type powder use magnum primers.
Especially the slower burning ones.
(W296, H110, N110, etc)
It is harder to ignite, especially in cold weather.

Mag primers with flake type powder is not necessary, or recommended.
(Unique, 2400, etc)

BTW: The Lee manual is just a reprint of all the powder & bullet manufactures load data you can get free.
It is lacking in a lot of importent details in several areas, including exact bullet brand & style used, primer used, etc.

rc

For me it depends on the powder I'm using. Spherical powders like H110 (which is awesome for magnum handgun cartridges BTW) can be harder to light off so I always use magnum primers there. I think the main point Lee is making is that you shouldn't substitute a magnum primer and go straight to the max load (which you shouldn't be doing anyway). Lots of folks assume a magnum cartridge needs to use a magnum primer, which is not the case at all. What really matters is whether the powder you're using need that extra flame to light off consistently. I tend to use magnum primers with all ball powders, regardless of whether the cartridge is a magnum or not.

INTERESTING! I'll be using Accurate #2 for my 38/357 loads. So a magnum primer might be in order? Should I try a regular SP first and upgrade to a mag primer if I observe unburned propellant?

Note I said Especially the slower burning ones.

Accurate #2 is a very fast burning powder, using very small charges, and as such it does not require magnum primers, even though it is a ball powder.

Accurate #2 would not be a good choice for 38/357 loads if you want any more performance then very light target wadcutter loads.

You would be better served with a medium burn rate powder like Accurate #5, or possibly Unique.

rc

Thanks for the advice. I'll definitely give #5 a whirl next time around. For now, I've already got a good load worked up with #2. Fortunately, I only need them for routine training, so they don't need to be marvels of accuracy. I've got 5 lbs of the #2, so I'm uhh, kinda stuck with it for now. :D

As noted above, carefull with the ball powders without mag primers. I shoot a lot of reduced loads for cast and recently workeded up a 7.62x39 load with a standard primer and BL(C)-2and had a bullet lodge in the barrel with a squib. Never happened before and never since I started using mag primers with ball powders. It's not really uncommon to see some unburnt powder with reduced loads. I second the use of Unique in the 357, but I would do what your going to do, burn up the powder you have first unless there is no suitable loads with the powder you have.

Will do. So, what are the mechanics behind mag primers? The impression I'm getting is that they don't cause a dramatic increase in pressure, but help to ensure a more complete burn? If so, I could have used that pearl of wisdom on a 38 Special load I had with a bunch of unburned Blue Dot a while back.

Unburned powder is more ofter a sign of using the wrong burn rate power at too low a pressure.

Blue Dot is relatively slow powder, and requires high pressure to burn clean.
You ain't gonna get it in .38 Spl standard pressure loads, even with mag primers.

rc

RC, where can I get a copy of the updated lee data? my modern reloading 2 doesn't list the newer powders and calibers (ramshot, .204 for examples)

mag primers are a bit harder too. if you have a gun with light springs (action job, CAS gun etc) you may not get reliable BANG.

I used about 800 small mag primers on 9mm one time before I caught that the box said magnum. oops. it was my first time using magtech, I saw mag and just assumed it was the name again. they worked fine other than being harder. my wolff sprung glock choked on a few of them.

greyling22
Heres Ramshot loading data,
http://www.ramshot.com/powders/