Best powder for 3" barrel S&W 686 .357

jski,

I like to match the weight of the bullet and the intended velocity to a powder that will produce an amount of pressure in which the powder performs well.

Don

I can do all of my. 357 loading with Unique. My next stop would be BE86, followed by Power Pistol.

I like Herco for my 3/4+ throttle loads. Unique works real well too

Fast and slow when it comes to handgun powders is a relative term. We are talking about milliseconds. The powder that is best for a 4" or 6" barrel will be best for a 3" barrel too.

jski said:

Anyone recommend Hodgdon's Clays powder?

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Clays is a super fast powder that will reach max pressure well before you generate velocities normally associated with a .357 Magnum.

I shoot unique in my short barrels.

I like Longshot loads for my 3" LCR. I don't the exact data that I recorded but I believe my 158gr load was getting almost 1000 fps without signs of excess pressure but I have them loaded to roughly 900 fps which is more shootable.

jski
H110 is a slow pistol powder so it falls a little above the middle on most burn rate charts..
Next come fast rifle powders (for example Reloader 7), medium fast rifle powders ( H335) medium rifle powders (H4895) and medium slow rifle powders (H4350) slow rifle powders (H4831) followed by very slow rifle powders (H50BMG, US869).

Clays is a fast burn speed powder for pistols, close to Bullseye/Titegroup, never used it but it should work for light loads.


For the .357 what are you after? Full power mag loads H110,, something not quite full power, maybe BE86, Light to medium HP38/W231 (lots of choices in the light to medium range)
(everybody has there favorites here)
You will lose velocity with the shorter barrel but H110 will still give you more velocity than something faster burning say BE86. With the shorter barrel the difference between them is less than you would see in a longer barrel.

jski said:

Anyone care to name a name?

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Care to name a particular bullet and velocity?

Don

357 = 2400
What is wrong with you people?

Yes, but it requires a Mag Primer and does not down load well. The 2400 would be a better choice if your going for lighter loads. If you only after BE Target velocities most of the fast burn powders will work. But you will be no where close to the Mag performance. Most powders do not burn clean at reduced loads. There are a few they will burn clean even in mouse fart loads. WST is my favorite for BE shooting velocities. WST was developed for shotgun use and burns exceptionally clean at loads below published levels.

Walkalong said:

Some good choices would be BE-86, HS-6, AA #5, WSF, Unique, True Blue, and others of a similar burn rate.

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Yep!

Don

To me, it just doesn't get any better than 12gr of 2400 behind a 158gr bullet out of my snub model 19. An under max load, very accurate and still lets you know you're shooting a magnum.

jski said:

Hear a lot about Power Pistol. A reloading bud of mine thinks it'd be an excellent powder for a 3" .357.

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It's in the same burn rate range as Unique, so no reason why it wouldn't work. However, AA#5 or HS-6 are better choices.

Don

jski said:

I do see Clays on Hodgdon's website for the .357. I assumed it'd be better for smaller barrel guns but all of Hodgdon's data for the .357 is based on a 10" barrel.

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jski said:

Hear a lot about Power Pistol. A reloading bud of mine thinks it'd be an excellent powder for a 3" .357.

Anybody have experience with this?

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You are focusing way too much on the barrel length.
The data on the Hodgdon site was not "based on a 10" barrel". They are telling you the barrel length they used to test the ammo for velocities. They didn't change the data because of the barrel length. If you look under their rifle data for a .357 Magnum everything will be the same but for the reported velocity because of the longer barrel. The charge weights are all the same as the pistol data.

Now that you told us you want to develop data similar to a .38 Special +P we can recommend medium powders like said above. Yes, Power Pistol will work well for what you are looking to load but not because the barrel is 3" but because you are looking for mild pressures and velocities. For light .357 Magnum loads especially with lead bullets I use HS-6 but all the powders Walkalong suggested will work well too.

Remember, there are faster and slower handgun class powders and rifle powders. A slow handgun powder is still much faster than a fast rifle powder. Don't confuse the two and you should read up on this like suggested above.