lowpower 357

I have a load that's a bit warmer than 38, but not a full 357mag.

It's 7.2grs of Power Pistol with a 158gr jacketed bullet of your choosing. It's mild and clean. I haven't chronographed it yet, but it should be doing about 1100fps from a 4" barrel, give or take a hundred fps.

Chris

low power 357

Try 8.0 grains of IMR sr4756, behind 125 gr HP , oal 1.58 , Fed. 200 primers. Soft and very accurate in my S&W 27-2 4 inch.

<Disclaimer>LOAD DATA USE AT YOUR OWN RISK</Disclaimer>

For my .357 Cowboy action loads I use 4 grains of Red Dot with a 158 grain LRNFP. This gives me less than the 1000FPS ceiling for CAS and ends up being around 900 FPS. (Still hot for CAS but anemic for a .357 Mag)

For light .357 loads check Cowboy loads at alliant alliantpowder.com
or Hodgdon
Hodgdon powder

what do you have on hand?

If we knew your powder supply,we'd maybe save ya having to buy more.there are a lot of 'cowboy' loads online that cover a wide variety of powders.
NOt h110 or 296 mind ya,but a wide variety nonethless.

A book .38 or .38+p load will develop less pressure and velocity in the larger .357 case. Prior to switching to .38s almost exclusively due to the availability of free brass, I used book .38 loads to develop starting loads for the .357. As a general rule, +p loads usually shot more like regular .38 loads in terms of velocities. YMMV

Buy some unique and use the start load. I'm pretty sure every manual will have data for it.

In my guns, a S&W 66 and a Taurus 66, my loads of 7.4grs of HS6 in a .357 case under a 158 SWC cast bullet is accurate and easy on the gun and hand. I also shoot a lot of .38 sps in these guns and just brush the residue out of the chambers before using .357 loads again. I personally don't like to use .38 data in a .357 case.

My soft load, for my Marlin 1894C, is ~4grain of Unique (.3cc dipper - always check weight with your scale) top with 158gr LRNFP Bearcreek Moly coated bullet.

If I remember correctly, I get about 1000fps out of my Marlin Carbine. I would think that you should get about 600-700 FPS out of a 4" barrel.

This, I believe, is way less than 38Special's pressure.

The only thing that I heard is that you need to make sure that you crimp it tight. I did that on mine and it burn very cleanly.

-Pat

To approximately reproduce .38 loads in .357 brass, increase the powder charge by about 10% (e.g., .5 gr. for a 5 gr. load). Assuming you're creating a cartridge with a longer OAL, the increased charge will offset the larger capacity, and Bob's your uncle.

If you find this too worrisome, haunt cowboy action boards for a while, and you'll find that guys (& gals) regularly load .357 down to levels that equate to very low-powered .38's. It's a perfectly sound practice, given that you've got the brass and want to use it.

Trail Boss is your friend.

I just tested some .357mag loads using Trail Boss.

The upper end loads were 850fps-ish.

No leading with hard cast 158gr LSWC & no unburned powder residue build-up as seen by other low-pressure loads. Best groups were those with near-max loads (4.0-4.2gr) with magnum primers.

Really soft shooting.

Hey jfruser, how complete is Trailboss burning in short barrels? I'm thinking about using it for some snubnose plinking loads.

Chris

"...issues might I have if I just use 38 powder charges in the 357 case?..." None. Mind you, I use cast 148 WC's with .357 brass and have for eons with no fuss. 2.7 grains of Bullseye out of my GP-100.
My old Lyman book gives 2.0 to 3.5 of Bullseye for a 158 grain cast bullet. 3.5 grains is the factory duplication load. You'll get a bit more felt recoil with the slightly heavier bullet, but you won't have any problems using .357 brass.

mtnbkr said:

Hey jfruser, how complete is Trailboss burning in short barrels? I'm thinking about using it for some snubnose plinking loads.

Chris

Click to expand...

I dunno.

I had both my S&W686 & Taurus 651 Ti wheel guns available, but used only my 686 to test loads. Next time, when I'll try 4.0, 4.1, & 4.2gr in my 686, I might send a few down the snubby's bbl. Anyways, I am more concerned with accuracy in the 686, though they might become snubby practice loads, too.

My practice was to fire a 10-shot group, 6 rounds then 4 rounds, at the same target. I would examine bbl & chambers & note any lead/powder residue. I would then use a dry bronze brush for 3 back & forth strokes on the bbl & each chamber before the next 10-shot group of a different powder weight.

I never noticed any significant build-up & the little I noticed was more prominent in the lighter loads.