Cowboy Action Light Loads for .357 Mag cartridges - PRIMERS Standard vs Magnum?

[SteveK]

I'd like to load up some 150gr LFP bullets for next season and keeping the velocity as far below 900fps as can reliably be done. I'm thinking that with about 4grs of Unique the cartridges would be under 900fps. So why not forget about using magnum primers and just use the standard small pistol primers? After all, my .45ACP shoots just fine with a little powder and standard primers. Why spend the extra doe for magnum primers when a big bang isn't what I'm after anyway? Right? (or not?)

Your thoughts?

[dannyd]

Both primers will work, you may want to look at a 125gr LFP works well for clean matches.

[Walks]

In 30+yrs of Cowboy shooting I never heard of anyone using Magnum Primers except in Long Range BP Rifle.

No Unique that low. Use Clays, Titegroup, WW231 or Bullseye.

[SteveK]

Thanks... I believe you're right about using a lighter bullet. I'd use a 125gr LFP mold if I hadn't gotten my 150gr (158gr?) for dirt cheep

[SteveK]

In 30+yrs of Cowboy shooting I never heard of anyone using Magnum Primers except in Long Range BP Rifle.

No Unique that low. Use Clays, Titegroup, WW231 or Bullseye.

Hmmm. I have a little 231 at home and POUNDS of Unique... What about 700X? I have a bunch of that too.
It's too close to Xmas to order a new powder.

[JoeJames]

No need for Magnum primers. You're just essentially shooting 38 Specials out of a case that is 1/10th of inch longer. Same theory as I have been using in light 44 Magnum loads. My rule of thumb for light 44 Magnum loads was a little less than a 10th more than my regular 44 Special load (44 Special using 6.5 grains of Unique - I upped it to 7 grains of Unique in a 44 Magnum case, and the velocity was comparable). And regular large pistol primers in my case.

[Silver Jack Hammer]

I wouldn’t think Unique would burn reliably at such low pressure

[dverna]

In 30+yrs of Cowboy shooting I never heard of anyone using Magnum Primers except in Long Range BP Rifle.

No Unique that low. Use Clays, Titegroup, WW231 or Bullseye.

What he said. And use .38 Spl cases.

[JoeJames]

I wouldn’t think Unique would burn reliably at such low pressure

In my Rossi R92, very consistent velocity averaging 1150 fps, and quite accurate.

[Silver Jack Hammer]

In my Rossi R92, very consistent velocity averaging 1150 fps, and quite accurate.

4 grains of Unique is giving you 1150 FPS out of your Rossi ‘92 with 150 gr. boolits in magnum brass?

[Hick]

I get 950 fps with an Ideal 358156GC flat nose cast bullet and 3.7 grains of 700x out of my Henry rifle in .357. That's with magnum primers. With standard primers it's a little lower velocity (more like 925). I get similar results with the same bullet and 4 to 4.5 grains of W231.

[SteveK]

I get 950 fps with an Ideal 358156GC flat nose cast bullet and 3.7 grains of 700x out of my Henry rifle in .357. That's with magnum primers. With standard primers it's a little lower velocity (more like 925). I get similar results with the same bullet and 4 to 4.5 grains of W231.

That's so handy to hear! Thank you very much ! First off, I have loads to 700x and Unique. When I make the loads I'll be shooting them out of a pair of Evil Roys and a Uberti 1873 Winchester knock-off.

Merry xmas to you all!

[SteveK]

What he said. And use .38 Spl cases.

I'll be using the Starline 357 brass I bought at an auction. Ya gotta save $ where ya can, right?

[SteveK]

I wouldn’t think Unique would burn reliably at such low pressure

I was worried about that too! It seems that 3-4 grains of Unique might mean more "echo" in the case than powder. But when you think about it, my 45ACP has always shot darn good light practice loads for me, albeit the cartridge is much shorter. I'll have to try out a few testers and see how it shoots in a 357... at least I won't have to fret over-pressure or cycling issues.

[smkummer]

I use 700x in my 44 special/mag. and 45 cowboy loads. It works great. It works for 38/ 357 as well except that it doesn’t meter well below about 3.6 grains with my lee pro 1000 so I use bullseye. Of course you don’t need magnum primers unless you just want to use them up or your load is close to minimum and you get a little extra security with a magnum primer to not stick a bullet.
If 38 cases cycle well in your rifle, then use those as 38 brass give better ignition with light loads given the same amount of powder. You can get good results as low as about 3 grains 700x and a 150 grain bullet in 38 special.

[rfd]

starline .357mag brass, cci standard spp, 4.0 to 4.8 grains of w231 dumped with a harrells schuetzen measure, under a 125 grain whatever bullet. i no longer bother to cast for handgun bullets and prefer the hi-tec coated kind from precision and acme, they're cheap enuf with less smoke and no leading issues. in a 45oz ruger blackhawk there's not much recoil and the load is more accurate than i am.



i'm a lousy handgunner, but with the above gun and 4.8 load i can single hand quick fire a buncha rounds at 10yds and do ok, which i think is good enuf for cowboy.

[jonp]

Considering the velocity your after can I ask why your not using 38sp? Use standard primers for that in any case, magnum not needed.

[MT Gianni]

Magnum vs standard primers is all dependent on the powder used. In general ball powders do best with magnum, flakes are ok with standard.

[TNsailorman]

Gianni, that has been my experience over the years of reloading. Ball powders seem to be a little harder to ignite than standard powders. I really like Unique powder but it burns dirty (ash cinders) at low pressures, almost like black powder. But get it up to operating pressure and it is a good all around powder. It does quite well with lead bullets in the .41 magnum and .45 LC. my experience anyway, james

[AaronL]

Take a look at Trail Boss. It is designed for light loads. I use it for cowboy action shooting as well as most of the shooters I compete against. It works well in any handgun caliber that would be used in cowboy action.