Preferred powder for .357 Magnum/cast lead bullet loads

[AJC1]

Thanks to all who responded.



My Lee manual lists 6.0 grains as the maximum for Unique under a 158 grain cast lead bullet. Please, which manual or reference allows 6.5 grains of Unique?

I am surprised that the oldest powder in the bunch is so highly recommended for .357 Magnum loads. When I posted my question, I was expecting one of the newer powders to get the nod. But your responses showing overwhelming preference for Unique is certainly convincing. I will give it a try and if I get impressive groups I will post pictures.

Thanks again for the help.

It was the go to.powder for many years and was always available kinda like tightgroup is on every shelf now. I love me some unique but if I'm looking for magnum power I choose 2400. This being a load what you can get scenario the list above was comprehensive. I see ramshot enforcer on the shelf now and #2 only at sportsmans. That choice is easy.

 

[walnut1704]

I am surprised that the oldest powder in the bunch is so highly recommended for .357 Magnum loads. When I posted my question, I was expecting one of the newer powders to get the nod. But your responses showing overwhelming preference for Unique is certainly convincing. I will give it a try and if I get impressive groups I will post pictures.

Thanks again for the help.

There's a reason it's been around so long. But Unique's popularity is in some respect might be due more to shot shell reloaders than pistol shooters. Also decades of use means decades of research and experience. Reloaders tend to be set in their ways.

It works well across a variety cartridges. It's "Unique" in that respect. But it is sort of a Jack-of-all-trades powder. Works well in damn near everything but not the best in anything. I've always found something else that I like better, even if it's just because it's cleaner. They claim Unique is now "cleaner" but I haven't tried any new production. I'll have to do that. Someday.

If you keep a can around you can be assured that you'll have powder for any handgun cartridge that comes along. It will also load just about any shot shell.

I find Universal not quite as accommodating. It seems to be great, or not. All of this also depends on your standards.

 

[hdbiker]

All mentioned are good but I prefer Blue Dot for hard cast .357 & .44 Mag loads. hdbiker

 

[nofendertom]

J-Bar---My old Speer Reloading Manual Number Nine lists 158gr LSWC loads at 6.5 Unique and 7.0 Unique. This is with 158gr swaged bullet.
My Lyman Reloading Handbook 45th Edition lists 158gr cast bullet (w/gas check) with 8.0gr Unique as max. load.
I have never used these loads---I have used 6.0 Unique with 158gr LSWC as my go to load for years.

 

[GeoDudeFlorida]

J-Bar---My old Speer Reloading Manual Number Nine lists 158gr LSWC loads at 6.5 Unique and 7.0 Unique. This is with 158gr swaged bullet.
My Lyman Reloading Handbook 45th Edition lists 158gr cast bullet (w/gas check) with 8.0gr Unique as max. load.
I have never used these loads---I have used 6.0 Unique with 158gr LSWC as my go to load for years.

---
Hornady makes a swaged 158gr. LSWC-HP which is pretty soft and needs to be kept under 1000fps and run on top of slower powders or it will lead the barrel. It's a great .38Spl bullet but it doesn't belong in a magnum at magnum velocities in my opinion. Same for the Speer swaged 158gr. LSWC in my experience. It's a good .38Spl target bullet but its too soft for magnum velocities of 1200fps+(JMHO, YMMV, must be prescribed by a doctor, with approved credit, see your dealer for details, limited time offer. etc.).

Unique burns slow enough not to cook off the lube of the lead bullet and builds enough pressure to obturate rather than melt the base. It's pretty amazing stuff if you think about how old it is.

TiteGroup burns too "hot" for soft lead if you're trying to reach magnum speeds, and HP38 is about like Bullseye: a good, fast-burning target load powder but it's done burning before the bullet gets past the forcing cone so it never builds big velocity numbers. Push any of them up too high and you get pressure spikes, leading, blow-by, all of that. Not awful but not nice either.

 

[wcwhitey]

Alliant Powder - Reloader's Guide right from the Alliant Loading Data 6 grains 158 Speer SWC which is swaged and very soft, velocities kept low not because of pressure but leading. A hard cast bullet and 6.0 grains of Unique is a decent load that will give you approx 1000 fps from a 4" revolver. Again, pressure is not the problem its the eventual leading. Bullet designs and fit are most important here, flat based cast bullets are best for anything around 1000 fps as like some mentioned will give you a better seal and less leading generally, no blow by skid marks as I call them. Not every gun is the same and what I have found with Unique is that with every load there is a sweet spot between proper pressure and velocity with cast bullets. Unique shoots much cleaner at the right pressure and a good strong crimp. You can always start there and work up slightly. I would think for bevel based bullets 6.5 grains would be about the practical top end. I load slightly stronger at 6.2 grains (basically .8 of a grain more than the Unique +P .38 Special Lyman data of 5.4). That is what has worked for me, nice accurate and clean loads. Fun to shoot but has some punch.

 

[walnut1704]

TiteGroup burns too "hot" for soft lead if you're trying to reach magnum speeds, and HP38 is about like Bullseye: a good, fast-burning target load powder but it's done burning before the bullet gets past the forcing cone so it never builds big velocity numbers. Push any of them up too high and you get pressure spikes, leading, blow-by, all of that. Not awful but not nice either.

I'll disagree. W231 (aka HP38) at #29 on the burn rate chart is a lot closer to Unique #32 than Bullseye #13. It may vary a little depending which chart you're looking at but the conclusion is the same. For some reason a lot of reloaders think of W231/HP38 as "fast" but it isn't really.

Comparative Burn-Rate Chart Lists 163 Powders « Daily Bulletin (accurateshooter.com)

 

[GeoDudeFlorida]

Well looky there. Bullseye wedged right in between W231 and HP-38 for the same bullet, by the same testing standards, using the same criteria. I’ll be darned!

I'll disagree. W231 (aka HP38) at #29 on the burn rate chart is a lot closer to Unique #32 than Bullseye #13. It may vary a little depending which chart you're looking at but the conclusion is the same. For some reason a lot of reloaders think of W231/HP38 as "fast" but it isn't really.

Comparative Burn-Rate Chart Lists 163 Powders « Daily Bulletin (accurateshooter.com)

——
Well, if you don’t think HP 38 is a good, fast-burning target load powder for the.357 then you don’t have to use it.

 

[Armored farmer]

 

[Drail]

Heavy loads of Blue Dot WILL eat your forcing cone like an oxy-acteylene cutting torch and it is also sensitive to air temp. and can give varying pressures and velocities. That is not an Internet theory - I've done it. Almost all heavy .357 loads using Blue Dot that were common in a lot of old manuals are gone today and there is a very good reason for that. There are better powders for full tilt .357 Mag loads. Alliant has also recommended against using Blue Dot in .4 Magnum. Avoid Blue Dot for max loads if you like your pistol. Blue Dot's best use is Magnum shotshell loads.

 

[walnut1704]

View attachment 972532
Well looky there. Bullseye wedged right in between W231 and HP-38 for the same bullet, by the same testing standards, using the same criteria. I’ll be darned!

——
Well, if you don’t think HP 38 is a good, fast-burning target load powder for the.357 then you don’t have to use it.

Well clearly do not understand Powder Burn Rate if you're putting load data up. But that's O.K.

 

[wcwhitey]

View attachment 972547

That right there is a great lever action carbine load, exactly what I loaded for my Rossi.

 

[GeoDudeFlorida]

Well clearly do not understand Powder Burn Rate if you're putting load data up. But that's O.K.

——
It did occur to me you probably didn’t understand burn rates but I didn’t want to be rude about it. I’m glad you got the hint and fessed up.

 

[Armored farmer]

That right there is a great lever action carbine load, exactly what I loaded for my Rossi.

Me too.
Its good for my carbine and my revolvers.
Mild, accurate, and relatively quiet.

 

[GeoDudeFlorida]

I'll give you one guess what I would recommend....

I don't load for .38/.357 any longer, but when I did, 99.9% of my handloads got Unique. If you really want Magnum power, then step up to 2400, IMR4227, or W296/H110... but Unique will get you 80% there.

Of the 4 powders you list, only Unique should be considered for heavy loads in any event.

---

 

[Charlie98]

I'll disagree. W231 (aka HP38) at #29 on the burn rate chart is a lot closer to Unique #32 than Bullseye #13. It may vary a little depending which chart you're looking at but the conclusion is the same. For some reason a lot of reloaders think of W231/HP38 as "fast" but it isn't really.

Actually, I disagree with your disagreement. Bullseye and W231/HP38 are almost identical, and quite a bit away from Unique. The burn rate chart you listed is not a good one... it simply lists them in order. Try the comparison chart... it compares powders against each other. I like it better, and the first time I really sat and looked at it, a bunch of light bulbs went off in my head as far as burn rate and characteristics.

http://www.accuratepowder.com/wp-content/uploads/2010/12/burn_rates.pdf

 

[GeoDudeFlorida]

Actually, I disagree with your disagreement. Bullseye and W231/HP38 are almost identical, and quite a bit away from Unique. The burn rate chart you listed is not a good one... it simply lists them in order. Try the comparison chart... it compares powders against each other. I like it better, and the first time I really sat and looked at it, a bunch of light bulbs went off in my head as far as burn rate and characteristics.

http://www.accuratepowder.com/wp-content/uploads/2010/12/burn_rates.pdf

---
Yup. "Burn rate" is a non-measurement. I didn't want to be so brash as to rub the point in, though.

Remember your Boyle's Law? The pressure (p) of a given quantity of gas varies inversely with its volume (v) at constant temperature; i.e., in equation form, pv = k, a constant. "Burn rate" depends on a number of variable conditions which can never truly be constant for all powders because their innate characteristics make them unique (or are they Unique? Among those variables are the same ones found in Boyle's: temperature at time of ignition, volume of the container the ignited gas is to fill, and the pressure of the gas at ignition, intervals of expansion, and during the burn process to self-extinguishment/terminal volume. Take ten powders with "burn rates" under a given set of conditions, each with a full ignition-exhaust point within a picosecond (1x10^-12 seconds) of each other; in other words, simultaneous for any practical application. Are they going to be listed on a chart with the same number? Nope. But they tied, right? Yes, they did; but, that's not how charts of non-measurable comparisons work - they're advertising, not engineering - each powder is assigned a number according to its difference simultaneous rate. Powders 11-19 burned at the same "rate" as powders 10 and 20 to within a picosecond - but, that doesn't matter. The chart doesn't allow for simultaneous rates.

Some folks think a chart is a Stone from the Mountain brought down to be obeyed and admired... others understand a chart of comparative characteristics which can't be measured identically is just another comparative measure of non-measurable comparisons.

Have a great day!

 

[Legionnaire]

Of the powders you listed I have the best luck with Unique for magnum loads. As mentioned earlier, I get the "best" magnum loads with 2400.

This.

 

[41 Mag]

If you shopping around for powder and run across AA-9 grab it up. Its right there with 110/296 and 2400 for top end loads in quite a few calibers.

Other than that, use your Unique or if ya find some maybe HS6.

 

[slickracer]

Thanks to all who responded.



My Lee manual lists 6.0 grains as the maximum for Unique under a 158 grain cast lead bullet. Please, which manual or reference allows 6.5 grains of Unique?

I am surprised that the oldest powder in the bunch is so highly recommended for .357 Magnum loads. When I posted my question, I was expecting one of the newer powders to get the nod. But your responses showing overwhelming preference for Unique is certainly convincing. I will give it a try and if I get impressive groups I will post pictures.

Thanks again for the help.

Then use 6.0. I have an older Alliant data manual that says 6.8 max.