357 Mag - Loading Mid-Range Cast SWC

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RDub

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Hello
Ever since the early ‘70’s, I’ve loaded the same load for a mid-range SWC .357 cast bullet load. That is 7.0-7.5grs Unique and a 158gr cast SWC. All this time that’s the load I always went to. Once in a while I would load some Herco, but mostly Unique.

Well I thought it high time I expanded my horizons a bit and try some other powders that would be well suited for this task.

For this shoot I loaded some RCBS 150 SWC that weighed in around 154 grs., in Winchester brass. Bullets sized to .358” and lubed with Orange Magic. Bhn about 15.



Powders included are;
Unique/wspm
Herco/wspm
BE-86/cci 500
Power Pistol/cci 500
Longshot/cci 500
SR 4756/wspm
True Blue/wsp
800-X/cci 500
N350/wsp
AA #5/wsp
540/wspm
Blue Dot/wspm
AL-7/wsp
571/wspm
AA #7/wspm

For this shoot I brought a 6” Taurus 608 eight shot. Targets at 25 yards. 4” circles.
Velocity data taken with an Oehler Model 33 chronograph. Skyscreens centered 10’ from muzzle.



Target velocity was 1200 – 1250fps. Most everybody was in there or a little below. Need to reduce N350, Blue Dot, and AA #7 down a half a grain or so. True Blue and 800-X could come down a few tenths.

Here’s a graph;



I’m pretty happy with the accuracy with this bullet.
Kinda funny that the best group was turned in with 571, which I never would have guessed would perform that well. And one of the worst groups was turned in by my favorite, Unique. This game always surprises you.

Anyway hope this is helpful to someone. It was an eye opener for me.

The Lab;

 
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You might consider casting some 12bhn test bullets and re-testing with the same loads. You're looking for increases in velocity & accuracy.

Right now it looks like the higher pressured loads are the "more accurate" loads. I'm talking pressure not velocity.
 
Good stuff, but a little fast for my tastes. I shoot most of my .357s in Model 19s. I like to keep the velocity in the area of 1000-1100 FPS. It’s tough to find a powder that really performs in that range. I’ve never considered Blue Dot, and I haven’t done much with AA5. I need to go back and do some more R&D.

My M19s have always done so well with 12.5-13.0 grs if 2400 it’s hard to get away from that, but it’s unnecessarily powerful for target shooting and may be a bit harder on my guns than a 1000 FPS load would be.

BTW, I agree that you might experiment with softer bullets, maybe bigger too. I have a friend who loads .359” in all his .357s.

Thanks for sharing your test results! :)
 
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M29since14 : I believe 5.0 grs of Red Dot will give you what you are looking for with a 150-158 gr cast bullet . That is one of my favorite loads when I'm wanting less power (supposed to be 1000-1050 fps) yet great accuracy with those weight bullets in my 357's . Of course barrel length and your gun can change it a bit . Good Luck. , Paul
 
S&W Model 686-3 357Mag

Wow. Thank you so much again for RDub's
Comprehensive Reloading of the 357Mag.

Alliant American Select is a Powder I like
and use for 357Mag 44Spl 44Mag and 45Colt.

Several months ago I thought I'd try AS
and similar Lead SWC Boolit in my 357Mag.

I stumbled upon a very accurate load using
Oregon Trail 158gr SWC .358dia 357mag/
American Select 4.0grs/CCI SP/Starline case,
FPS: 850?

In my S&W Model 686-3 357Mag 6-1/2 circa
'93 this reload is very accurate, two handed
hold, 22lr rifle target at 50ft, right in there
with little effort.
 

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I'm loading 158 SWC to about 1050 in my six inch 686. Hardness is said to be 18. I'm using 6.7 grains of AA5. Pleasant and accurate load.
 
Wish I had the time to drag my lab out to my range. One of my favorite things to do! Those are a bit warmer than I normally like as well, but that's the beauty in it, there's something for everyone when 8t come to reloading. Great information, and darn good shooting!
 
Hey Guys thanks for the kind words. This is always fun to do.

Part of the benefit of sharing loads like this is, everyone can interpolate where they want to be velocity wise and have a reference point to start from. Those that want less velocity can take a grain or a grain and a half off or so, and see where they are. Wasn’t at all suggesting everyone should shoot these. This was my first stab with most of these powders, so I’m going to drop off a few tenths on the faster ones.

This gun has chamber throats that are just right for .358” cast bullets. I get a good gas seal as I get very little barrel leading, so I don’t need a larger bullet. The first Ruger Blackhawk I bought in 1970 leaded like crazy. I could remove the cylinder, drop .358 bullets of any flavor down the chambers and they just dropped on through, didn’t even slow down.

Nightowl- I use RCBS and LEE for handgun loading. I have a LEE factory crimp die and usually finish off with that die, but I can’t recall what I did on these. It was last year that I loaded them.
 
If your cylinder throats are large enough and you are getting severe lead problems in the barrel . It can be the result of a tight spot in the barrel where it threads onto the frame . It was over torqued when they indexed the front sight to the rear sight causing a tight spot , a choke . Fire lapping the barrel is an easy fix for that problem . Many times only a dozen or so fire lap rounds is all that's needed . I have just finished fire lapping 4 different revolvers with that exact problem . Now , I can shoot from mild to wild and the barrel is bright , shiny and very clean---- no lead . Veral Smiths soft back book , " Jacketed Performance with Cast Bullets " explains it well . His website " LBT Molds " , is where to look for it . He also makes the finest cast molds available . Regards, Paul
 
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My usual .357 load for years has been a 158 cast SWC with 7.0 Unique. Accurate, controllable, pleasant enough to shoot in a K-frame. Well below maximum, which is exactly what I intend. Plenty of power without unnecessary blast, recoil, or stresses on the firearm. I stopped looking for the outer edges of the performance envelope years ago.
 
Lots of good groups on that outing......

I shoot a 158 Lwc from 788fps with Trail Boss up to 1320 with Unique.
Back then I did not have ant 2400 or w291 type powders.

HS-6 at 1108fps is one of my better POA, accuracy loads, in the 6" 357
with the 357 cases.
A sleeper was Green Dot at 1281fps that was almost as good as the Unique full load.
I have tried 16 powders with this lead bullet.

Good shooting.
 
I like the look of the grouping for the Herco too. Herco, AA#5, and Unique are the only 3 you tried that I currently have.
Just curious why no H110 or 2400?
They are both pretty much "old standbys" for the 357 magnum, aren't they?
 
BC38 said:
I like the look of the grouping for the Herco too. Herco, AA#5, and Unique are the only 3 you tried that I currently have.
Just curious why no H110 or 2400?
They are both pretty much "old standbys" for the 357 magnum, aren't they?
Click to expand...

Yes, but only for full-house loads. If you're loading mid range hardcast target loads, best bet is to use a medium-fast burning powder such as Unique, AA5, or the like. I'd avoid reduced loads for slow burning powders.
 
BC38 said:
I like the look of the grouping for the Herco too. Herco, AA#5, and Unique are the only 3 you tried that I currently have.
Just curious why no H110 or 2400?
They are both pretty much "old standbys" for the 357 magnum, aren't they?
Click to expand...

Hi
I didn't shoot 2400 because I find it doesn't burn as clean with medium pressure loads. Although very accurate, I personally don't like to use it for anything less than max pressure loads.
The same goes for H-110 or 296. They are for max loads. In fact I don't use H-110 or 296 anymore in .357. I've switched to Alliant 300-MP.
 
M29since14 said:
Good stuff, but a little fast for my tastes. I shoot most of my .357s in Model 19s. I like to keep the velocity in the area of 1000-1100 FPS. It’s tough to find a powder that really performs in that range. :)
Click to expand...

W231 is a great powder for .357 loads in the velocity range
you're looking for. A load of 5.8 grs of 231 under a 158 gr Magma
style cast SWC with a WSPM primer chronographs 1061 fps out
of my 4" 27-2 with only 6 fps ES. Pretty hard to beat in this
velocity range.
 
I've found 4.0gr of Clays under a 158gr plated / lead/ coated bullet produces very good results.
 
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