Unique in 357 Mag

[curioushooter]

Something funny with data. I have not found any good cast boolit data using Unique past 120 grains or so. Alliant lists the soft lead Speer swaged job at 6 grains as a max which is surely well below the SAMMI limit as a 158 GoldDot is rated at 7.7. I would imagine it would be safe to go to at least 7 grains with a ~160 grain reasonably hard cast boolit. Anybody have better data or quickload or something?

[Winger Ed.]

I'm a big Unique fan, but even with cast .357s, I always find myself drifting back to med. charges of Blue Dot.

[james nicholson]

Lee data for a 158 grain starts at 6.2 and goes to 7.8 I have not tried this yet, so do not know how well it works.

[Wheelguns 1961]

I use 6.5gns with a 155gn mp-359 hammer lg. hp. It is a fantastic load out of my gp100’s and blackhawks. I think I get about 1,100fps. It is accurate without a big muzzle blast and medium recoil. I call them my 3/4 magnums.

[Outpost75]

The higher flame temperature of Unique compared to 296 or H110 will burn out your revolver forcing cone in short order when full-throttled above 7 grains with 158 grain bullets in .357 Mag. I learned that very expensive lesson on a Colt Python many years ago.

[Froogal]

Lee data for a 158 grain starts at 6.2 and goes to 7.8 I have not tried this yet, so do not know how well it works.

My Lee manual gives a starting point of 5.5 up to 6.5 of Unique with a 158 grain bullet. I started at 5.5, worked up to 6.5, and went back to 5.5.

[skrapyard628]

I have ran a few hundred powder coated 158grSWC (from eggleston) through my 5" barrel S&W using 6gr Unique. It averaged about 1070fps on the chrono and was a pretty accurate too.

[Hanzy4200]

I like unique for medium loads in .357. Power Pistol is my go to for full house loads.

[curioushooter]

higher flame temperature of Unique compared to 296 or H110

How did you learn of this?

[Walks]

Experience.
I used to shoot 6.5grs under a #358429 in a Ruger Blackhawk 6 1/2".
7.0grs Unique gave A Lot of Muzzle Flash and B/C gap. Toning it down made a big difference in accuracy.

[Outpost75]

How did you learn of this?

From ATF bomb lab.

[wmitty]

Outpost 75

Thanks for the heads up!

[winelover]

The higher flame temperature of Unique compared to 296 or H110 will burn out your revolver forcing cone in short order when full-throttled above 7 grains with 158 grain bullets in .357 Mag. I learned that very expensive lesson on a Colt Python many years ago.

I did that with Bluedot, with my Python.

Winelover

[Silvercreek Farmer]

Load?

I did that with Bluedot, with my Python.

Winelover

[winelover]

Load?

I would have to look that up, in Speer's older manual, from the 70's. I could tell you it was maximum charges, with 158 grain JSP's. Shot like a dream.

Winelover

[winelover]

Out of Speer's Reloading Manual Number Nine:

Speer 158 grain JSP

12.0 grains of Bluedot for 1264 fps. (maximum charge for 357 Magnum)

Use to buy Hercules BlueDot by the eight pound jug, don't keep it in the shop, anymore. After re-barreling the Python, I made the switch to cast and 2400 for all my magnum pistol cartridges.

Winelover

[WRideout]

Here is some load data I have actually used in my Mod 19 6". Any more I back away from full-house loads in 357; no particular need for them since I don't hunt with the revolver. Lately moderate loads of 2400 seem to be the ticket.

Date case primer powder charge bullet bullet wt. Bullet Lube Bullet Diam LOA Notes
7/9/2011 WW SP 2400 13.0 gr 358477 150 gr SWC Home Brew #1 as cast 1.582 very strong recoil in M19 S&W
10/19/2010 WW SP Unique 7.5 Hornady 160 gr SIL seated to cannelure moderate load
3/11/2013 WW SP Unique 8.0 gr 358477 150 gr SWC Home Brew #1 as cast seated to crimp groove 1460 fps book load
3/11/2013 WW SP Blue Dot 10.7 gr 358477 150 gr SWC Home Brew #2 as cast seated to crimp groove 1356 fps book load
12/29/2013 WW SP Blue Dot 10 JHP 158 gr seated to cannelure mild load
1/13/2018 WW Mag IMR 4227 13 358477 150 gr SWC Home Brew as cast 1.63" no sticky extraction
1/10/2018 WW SP Red Dot 3 #12 shot 75 gr na na meat tray wads

Eight grains of Unique gives very stiff recoil, and I have recently backed off on that charge. Sorry the table doesn't format very nice, but the information is all there. Since I used up my can of Blue Dot, I am working through my other magnum powders.

Wayne

[Petrol & Powder]

On the rare occasions that I want to load & shoot magnums; there is only one powder I turn to - H110 / WW296.

H110 (and its twin 296) isn't as versatile as other powders but it excels when used for full charge magnum loads.

My advice for the OP is if you have Unique and want to use it in 357 mag casings, think of it more as a 38 +P powder in a magnum casing, rather than as a full charge 357 mag powder. So while I would use 6 grains of Unique behind a 158gr LSWC for about 1000 fps, I wouldn't consider Unique as a candidate for more speed with that bullet in a 357 mag.

In non-magnum loadings Unique works best near the upper pressure limits but I've never considered it a optimal powder for magnum loads.

And Outpost75, I didn't know about the increase erosion from full charge Unique loads in a 357 mag; thanks again for sharing hard earned knowledge.

[centershot]

Throat erosion from prolonged use of heavy loads of Unique in the .357 is a fact! A very good friend had to send his M27 back to S&W to have his barrel replaced due to forcing cone erosion. This was after 20+ years of cast bullet shooting, almost exclusively with heavy charges of Unique! Not inexpensive!

[PositiveCaster]

It seems to me that 20+ years of heavy use is not a high price to pay for a high performance, low-recoiling load. I used Unique for many hundreds of loads with a 125-grain GC and enjoyed every shot. Didn’t notice any abnormal erosion, but it might have been there. So what?



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