Duplex Bullets in a 357

Ganderite

Ganderite

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This my current project. 115 gr SWC on a 95g CamPro. Total 205 gr.
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357 case with 2400. Cases were already primed with a S&B standard primer. 2400 really needs the magnum primer, otherwise ignition is poor and the ES is high.

I loaded 5 rounds with 9.5, so I could shoot 3 at a paper target (5, 10 and 15 yards) and then 2 at the chrony.

On paper, at 5 yards the two bullets were 1/4" apart.

at 10 yards they were 1/2" apart, but way off the point of aim. I will be loading more of these with 11.2 gr for about 12000 fps. I will have to test again to check accuracy.

At 15 yards, 1 inch apart. (You can't see the bullet kissing the edge of the paper in the picture.)
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I also loaded 2 each of 10.0, 10.5 and 11.0 for the chrony. I was looking for 1200 fps. Did not quite get there. 11.2 would be about right.

I put the SWC on top so I had a good groove to crimp into. This is a stout load for a heavy bullet and did not want the bullet to pull out of the case on recoil.

For a 38SPl, 7.0 gr of 2400 is about max at 850 fps.
 
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This is not a duplex loading.
I have been loading a 200 grain cast projectile in 38 spl cases using 12.8gr 2400 .
I set the projectile ahead to leave internal case capacity to be equal a 357mag. This also allows me to crimp in the groove.
I use these in a 357m rifle,
 
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Thanks. I just tried 11.2 and was still short of the 1200fps I was looking for.

Do you have any idea what velocity you get with 12.8 of 2400? Our bullet weights are about the same.

Sorry about the double posting of this thread. I am better with a gun than a computer.
 
I need to make a BIG correction..
The load is 12.8gr of W680.
Sorry , NoT 2400, (I was looking at 2400 on the bench when I wrote that.,)
i've bought alot of gear in my years, but haven't purchased a chronograph , yet.
 
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Hornady has a self defense 410 load with 2 buckshot behind a ftx bullet and Winchester has a 410 self defense load with 3 or 4 disks and 12 bbs. That 357 duplex load would be much more affordable and probably similar effectiveness.
I've shot 200gr .358" bullets out of a 12" barreled 357 ranch hand, they hit steel plates with authority.
 
Much fun!

I did "Duplex and "Triplex" Loadings in the 43 Mauser and 45-70 (long-necked or straightwall) and posted it here in 2007: https://www.canadiangunnutz.com/for...d-to-Win-Any-Bullseye-Match!?highlight=Duplex

Wadcutters are perfect for that. The pics went away with photobucket, so here they are 145 gr, 195 gr and three 145 Gr (335 grs total). At 100 yds they gave about 8" groups roughly centred around where I had aimed.

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OK. Testing is complete. I used 2400 over a S&B standard primer, because the brass was already primed when I decided to do this. When I load from scratch I will switch to the CCI Magnum primer, because 2400 can be erratic when downloaded.

Bullet weight 205gr (115 + 95)

9.5 - 932 fps
10.0 - 1020
10.5 - 1035
11.0 - 1124
11.5 - 1141
12.0 - 1167

3 shot average form a 4" barrel.

I will use 12.0 gr as my standard load. Cases extract smoothly.

the 12.0 gr load put the 2 bullets 1" apart at 15 yards.
 
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Performance Update

Today I shot the duplex bullets (SWC and Campro) at 25 yards. The "group" was the size of the 8x11 target.

When I last tried this I shot a pair of SWC bullets back to back, at at 25 yards they were about 2" part - not 10".

I tried this load (12.0 gr 2400) in 3 different revolvers. Results were the same in all 3. But I discovered that what felt like a full power load in the Ruger GP100 felt downright violent in the S&W M13 and the Ruger SP101.

If I load any more of these, I will drop to 11.5gr.

I am next going to try a pair of the 115SWC back to back, to see if they will print closer together at 25 yards.
 
That did not take long....

I went back to the range with some 357 cases loaded with 11.5 gr of 2400 under a pair of 115gr SWC bullets, loaded back to back. 1179 fps - Full Power!

I shot them at 20 yards, along with one of the original test with a Plated 95 gr Campro under the SWC. they printed 2" apart. Not bad.

The duplex SWC printed closer together. These look like the way I remember when I did the same thing about 30 years ago. For some reason the plated 355 Campro does not group with the 358 SWC.

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OP,
Run the SWC backwards to drive the jacketed RN for an accuracy improvement.

Stacked/multiple gallery load/round balls don't shoot accurately thru a wheel gun or a semi auto.
 
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