Short barrel specific data for .357 Mag

[Adam5]

I’m looking at changing my loads for full power .357 Mag rounds. My full power loads have been a 158gr Hornady XTP over 15.8gr of W296 and a magnum primer. My friend that taught me to load and that I load with has been using this load for many years in longer barrel revolvers. It’s great for those, but is a handful in my smaller and lighter Colt King Cobra with its 3” barrel.

I’ve been researching load data for shorter barrels, but am coming up blank. Lyman lists it’s data as being from a 4” which is close. Everyone else uses 6”-8” barrels for testing. Hodgdon even uses a 10” barrel for their .357 Mag test data.

Does anyone have a good data source for shorter barrels?

 

[BriarPatch99]

The data can be the same ....it is the velocity that will differ because of the barrel lengths.

If data is safe in a 10" barrel gun the same data is safe in the 3" gun ....

Since the data is what "they" found in their test gun ....does not mean it will provide the same exact results ...even in a gun with the same length ... ALL guns are different ...

 

[Gordief]

i'd throttle that load back to about 12.5gr. if that's the only powder available.

 

[Adam5]

i'd throttle that load back to about 12.5gr. if that's the only powder available.

Using different powder isn’t an issue. Finding loads optimized for a short barrel is.

 

[BriarPatch99]

That is the problem ...what ever powder that gives the highest velocity in a longer barrel will also give the highest in a shorter barrel....

Now if you want lighter loads ...cut back the amount of powder ....or ...You can use a faster burning powder ....but that only raises pressure and drops velocity...

There is plenty of data that will give lower velocity out of a shorter barrel...

What am I missing?

 

[BriarPatch99]

It is not a good idea to reduce H110/W296 a whole bunch ... Hodgdon/Winchester used to say not to reduce any ...but now I think they allow up to a 5% reduction... either powder(same powder) reduced can be as dangerous as a over charge...

If you want a lighter load then switch to a faster powder ...

 

[king killer delete]

That thing will kick you. My hand hurts just thinking about it

 

[Dixie Shooter]

Try Longshot or HS-6. Overall they're versatile powders. Either should push a .357 reasonably fast and still maintain a decent load density. It should also be safer to throttle back with these powders.

Have you considered the 140 grain XTP? I've been tinkering with them and various 125 grain bullets. I like the 140 grain XTP pretty well.

 

[Adam5]

I ended up going to a lighter bullet and a faster powder. I also stayed off the max load.

I went with a Hornady 125gr XTP over 9.5gr of Power Pistol. They should run just shy of 1300fps from a 3” barrel.