[david Lawson]

Guys. I'm looking for input into powder preference for building ammo for a 2.75"357 mag. Going to be using cast 158 swc and Keith 173s. Hoping to keep the velocity around 1100. Pistol will be a part time ccw. Mostly a truck gun. Thanks for any help. Stay healthy. Dcl

 

[David R]

I can tell you from loading for short barrels in 38s, 44 special and 45s it takes the same powder for velocity as the long barrel. You will get a fire ball, but to get the velocity up, what makes em go fast in a long barrel makes for fast in a short barrel. Yes some of the powder burns outside the barrel, but its a trade off.

If you are going to loose 50 to 100 fps, you need to start faster.
Lyman lists IMR 4227, Blue dot, 2400, WW 296 and H110. All slow powders that will make a fire ball, but get you where you want to go. I am a little shy of Blue dot. It seems to go inconsistent when I get near max loads. This is with my crony.

I took a lot of time finding the best load for my 1 7/8" 38. I DID end up with blue dot. I don't shoot many of them.

I did the same for a new Smith and Wesson 45 Shield compact. Factory hollow points hit a whopping 738 av from the 3.3" barrel. I tried unique, Power Pistol and CFE pistol. I ended up getting 860 with CFE pistol using a 230 grain XTP. All I wanted was 5" ballistics from the 3.3" gun. These were all from published loads.

Good luck
David

 

[Transamconvert]

Subscribed for interest to see what your conclusions are.

My speer book has a limited number of comparisons between short 2.5" barrels and full size, in this case 6". Their results definitely show that some powders lost less velocity in short barrels than others. Unfortunately no short barrel numbers for 158gr, however it may be advantageous to use a lighter bullet in a short barrel to be able to use a faster powder?

 

[mikegalway]

Tite Group . Go to Hodgdon's reloading page on line . JMO

 

[David R]

Went to Hodgun site. They use a 10" test barrel. I looked for a 170 JHC, they list no lead bullets in that weight. I see some pretty impressive velocities for a 170 grain bullet.

It looks to me you are going to have to use a slow powder to get 1100 fps for a 168 or 173 grain bullet.
158 lead looks a little easier. From the chart above, you loose about 200 fps except for Unique.

Alliant shows a max of 1040 fps for a 158 grain bullet using Unique. Can't find barrel length.
Hercules 1987 shows 1345 for Blue Dot and 1335 fps for 2400. I can't find barrel length. These are for a 170 Jacketed.

For 158 lead, Hercules 1987 shows 1425 for Blue dot and 1560 for 2400. Either these are really optimistic or its a rifle.


Enjoy your adventure.

David

 

[mikegalway]

Check out H 110

 

[david Lawson]

Thanks guys. All my 357s are 6"-71/2". Now I've got some data to check up on. I've got several of the powders you guys listed. Appreciate it.

 

[jjfitch]

You will get a lot of unburned powder and loss of efficiency with "magnum" powders in barrels shorter than 3"!

A heavier bullet and faster powder will reach peak energy sooner than lighter bullets and slower powders.

Google: "Reloading data for snub nose revolvers"

Smiles,