357 Mag Rifle Loads

[SC73]

Hello everyone,

I'm new to the forum, and have already learned a lot!

I have an Uberti 1873 lever action in 357 Mag, and I'd like some suggestions as to a good medium power load. Considering the somewhat "weak" toggle link action, I'd prefer not to exceed 20-22,000 PSI, while achieving decent velocity. I've had good success using 38 special (or+P) data +10% for added case volume for light plinking loads, but the super fast powders used do not allow me to properly take advantage of my 20" barrel. Having heard the warnings about greatly reduced loads with slow burning powder, I'm very hesitant to reduce 357 Mag data significantly.

What about a full charge of even slower powder, such as Accurate 1680? Am I correct in thinking that with a full case, the risks of using slow powder would be eliminated?

I'm thinking mostly of heavier jacketed bullets 158's and 180's, but I'd love to hear some suggestions for any bullet weight.

Maybe it's impossible to take advantage of a long barrel without high pressure?

Thanks in advance!

 

[buck460XVR]

I doubt if you need to be concerned about the "weak" toggle link action, even their "Lightning", a weaker action, is built to take modern sporting ammunition. Low velocity charges with super fast burning powders is inviting a stuck bullet. I have good luck with 7.5 gr of Unique under a 158 jacketed in my .357 lever for plinking loads. Any decent manual will give you a good place to start.

 

[Jim243]

Am I correct in thinking that with a full case, the risks of using slow powder would be eliminated?

No you are NOT correct. Slower burning powder will build up higher pressures than faster burning powders. In most cases the 357 Mag case will be filled with less than 1/2 the volume of the case with powder.

You need to get some reloading manuals and follow the load data shown for your bullet and the powder amount that they recommend.

Jim

 

[mikld]

You can rest assured that your gun is strong enough to take proof loads, or else it wouldn't be sold. I kinda think you're overthinking this. Normal pressure limits for .357 Magnum is 35,000 psi. For light loads, .357 is one of those very versatile calibers that will allow you to load down to where the bullet barely exits the barrel up to real "Barn Burners". If you want light loads, try some plain old .38 Special data in your .357 Mag. brass. Use "normal" .38 powders (Bullseye, W231, Titegroup, CFE pistol, etc.). While I don't have a .357 rifle I do have a revolver that I have reloaded for nearly 28 years, and I've gone the gamut from 148 gr. wadcutters in both .38 and .357 brass over extra light loads of Bullseye and W231 up to 160 gr. SWC over near max/slightly over max. loads of 2400, Trueblue and WC 820.

For a new reloader, just stick with what the book says, you can have everything from light-medium starting loads to full magnum loads, and if you don't have a manual, get 3 and start with the starting load data.

 

[SC73]

Thanks for the quick replies!

buck460XVR, thank you for your sharing your load data, and for giving me some peace of mind with using heavier loads. I'd like this rifle to be in good shape for many years, and didn't want to beat too hard on it! I usually use lighter bullets for my plinking loads, current favorite being 8.8 grains of Accurate #5 under a 110 grain XTP, giving me 1484 fps. +-0.5%

Jim243, thank you for correcting me on the slow burning powder question. I certainly understand the risks of deviating too much from reloading manual data! BTW, which reloading manual is giving you data for half full cases? That may be the data I'm looking for. Lyman shows starting load at 16.3 grains of H110, approximately .050" from the bullet when seated to the cannelure. As mentioned in my previous post, I hesitate to go much under starting loads with slower powders.

 

[SC73]

mikld, I think you are correct that I'm over thinking this! My thinking says if I could keep 20,000 psi behind the bullet for a full 20 inches I should achieve respectable velocity while being more gentle than necessary with my toggle link action. I realize a steady 20k psi could be impossible to achieve. Just looking for ideas.

Also, I should have introduced myself a little better. I do have a fair amount of experience reloading, and I do have some manuals. It seems that loads between 38 special and 30,000 psi 357 loads are rather few, and often designed for handgun use, where burning all the powder in a short barrel is desirable.

My manuals show that 2400 and IMR-4227 can both be reduced to around 10 or 11 grains safely, but I happen to have neither at the moment. If anyone else has a favorite rifle load I'd like to hear about it!

 

[stubbicatt]

For many years I have enjoyed about 12 to 12.5 grains of 2400 under a 160 grain Lyman "big groove" RNFP cowboy bullet and inexpensive home made lube. It is a moderate load, and quite accurate.

I should receive my Taylor's Uberti 1873 sometime this week, and this is the load I intend to use in it.

I can't say enough good about that Lyman bullet. Never had any leading or indications of the lube playing out before exiting the muzzle in a shorter barreled Marlin rifle in the same chambering.

YMMV.

 

[buck460XVR]

Am I correct in thinking that with a full case, the risks of using slow powder would be eliminated?

No you are NOT correct. Slower burning powder will build up higher pressures than faster burning powders. In most cases the 357 Mag case will be filled with less than 1/2 the volume of the case with powder.

With the slowest burning handgun powders, especially in .357, the case will be almost full. H110/W296 starting loads are generally in the neighborhood of 85% in most every manual. IME, best performance is when volume is around 90%. With IMR 4227, start loads are over 93% and best performance comes at 100% or even slightly compressed(100%+). This is why reloading with those powders is quite safe, even for a new reloader as you generally cannot get enough powder in the case to damage a modern firearm in good condition. Double charges run all over your bench. I don't know of many legitimate magnum handgun powders, when used at legitimate magnum handgun loadings that have start loads of under 50% of case capacity. Here is an example.....