'light' .357 rounds

[roscoe]

So, out here in Nevada, reloading supplies are kind of hard to come by these days. I am out of .38 brass, and have a bunch of .357 , but my kids want to shoot, and they like lighter loads. I have Bullseye, Titegroup, and Unique as pistol powders in my reloading box.

The question is - for hardcast 158 SWC and 148 grain WC slugs, can I just load the .357 case with the lighter .38 powder charge? Or does the extra case capacity do something that I need to accommodate?

Thanks!

 

[edwardware]

The question is - for hardcast 158 SWC and 148 grain WC slugs, can I just load the .357 case with the lighter .38 powder charge? Or does the extra case capacity do something that I need to accommodate?

Yes you can, but the load will be even lighter in .357 brass. How much? Approximately the difference in case volume.

If you're at Starting load in .38Spl, come up 15% of the way toward Max .38Spl in .357 brass. If you're already near Max in .38Spl, just load it as is in .357.

 

[bersaguy]

I am out of .38 brass, and have a bunch of .357
Thanks!

I have a bunch of 38 brass, and not much 357, actually just cleaned some up. Shoot me a PM if you want to trade some out

 

[Heir Kommt Die Sonne]

Yeah it's very possible to have light .357s that perform pretty much as .38 Special. A load I've been doing is 8.1 grains of Blue Dot under a 158 grain wad cutter. Gives me a mellow 800-900 FPS. Not my ideal load but I've been using Blue Dot because I have lots of it (stocked for the semi-auto calibers).
Pretty sure you can come up with something with Unique, or you can take bersaguys offer on .38 brass (I would)

 

[Walkalong]

can I just load the .357 case with the lighter .38 powder charge? Or does the extra case capacity do something that I need to accommodate?

Yes you can. Some folks add 10% to accommodate the extra case capacity, but you can safetly download .357 Mag brass just as we do .38 Spl brass. I use WST or Competition to run a plated 158 at around 700/750 FPS from .357 Mag brass. Accurate, and those two powders are a couple of the least position sensitive as far as FPS go. Clays is also good there.

Your Bullseye & Titegroup will do what you want, and both download pretty well, the Unique will do great for ".38 Spl full power" loads in .357 Mag brass.

 

[Slamfire]

I wanted to duplicate 38 Special velocities in 357 Magnum cases, primarily to get the noise and recoil down in my 357's without having to deal with a lead ring in the cylinder. I shot a case of +P 38 Special in a M66 and that left a lead ring that prevented 357 cases from ejecting. Removing the lead ring in each cartridge hole was time consuming and frustrating.

My standard load is a 158 gr LSWC or LRN with 3.5 grains Bullseye in a 38 Special case. This is a standard pressure load, very accurate in every 38 Special it has been used in. I suppose 3.5 grains Titegroup would provide the same velocity, the two powders are very close in terms of charges, but I have been using Bullseye for decades and am very familiar with the powder. Bullseye is outstanding in light to medium loads in 38 Special cases, it was a staple for the PPC crowd. For a powder that has been on the market since the late 1890's/early 1900's, Bullseye is still doing great. I think it is either the first smokeless pistol powder, or the oldest pistol powder still around.

After testing, I decided that in a 357 case, 4.0 grs gave the best overall accuracy, and was just a little faster than my standard 38 Special load.

Colt  Trooper  MKIII  6"  Barrel    

158  LSWC  Factory  Zero  38  Special  ammunition 
13-Sep-18  T  =  72  °  F

Ave  Vel  =  739
Std  Dev  =  38
ES =  152.4
High=  804.1
Low = 651.6
Number rounds =  18
 
158  LSWC  Factory  Hornady    38  Special  ammunition,  box  dated  12-1982 
13-Sep-18  T  =  90  °  F
 
Ave  Vel  =  734
Std  Dev  =  16
ES    =  50.56
High    =  755.8
Low    =  705.3
N  =  16
                                                        

158 gr LRN  3.5 grs Bullseye 38 SPL cases WSP                                                   
13-Sep-18            T = 72 ° F                                           
                                                               
Ave Vel =764                                   
Std Dev =24                                       
ES  =       87.45                                   
High  =  804.1                                    
Low  =   716.6                                   
N =         21                                         

158 gr Valiant LRN 3.8 grs Bullseye lot 907 6/20/05                                        
once fired mixed 357 cases, WSP                                           
19-Sep-18            T = 80 ° F                           

Ave Vel =  788                       
Std Dev =  38                          
ES  =147.4                   
High  =830.3                   
Low  =682.8                   
N =         25                         

accurate no leading

158 gr Valiant LRN 4.0 grs Bullseye lot 907 6/20/05                                           
once fired mixed  357 cases, WSP   
                                     
19-Sep-18            T = 80 ° F                                                                 

Ave Vel =             800                       
Std Dev =             26                          
ES  =       102                       
High  =  846.2                   
Low  =   744.2                   
N =         24                         

very accurate, no leading          

158 gr Valiant LRN 4.0 grs Bullseye lot 907 6/20/05                                        
357 Midway  cases, WSP                                                                                      
11-Oct-18            T = 71 ° F                            
  
Ave Vel =817                    
Std Dev =23                        
ES  =       72.55                    
High  =  853.6                    
Low  =   781.1                    
N =         12

Based on this, if you want to fire 148 LSWC's in 357 Magnum cases, I am going to claim that all you need to do it bump up the classic 148 LSWC load of 2.7 grains Bullseye in a 38 Special case by one half grain. So a load of 3.2 grs Bullseye with a 148 LSWC in a 357 case should give about 700 fps.

Colt Python Stainless Steel, 6" Barrel

148 gr LBBWC 2.7 grs Bullseye 38 SPL cases CCI500
24 Sept 1999 T = 78 ° F

Ave Vel =710
Std Dev = 18
ES = 72.02
High =746.1
Low = 674
N = 32
shot fine at 25 yards, no leading, light recoil

 

[forrest r]

It's always good to have some 38spl brass laying around for the 357's. But it's also good to have quality reloading data. A link to what I consider alliants "BEST" reloading manual, 2005 version.

http://castpics.net/LoadData/Freebies/RM/Alliant/Alliant_2005.pdf

In it you'll find the reloading data you seek for 357 cases and "target" loads using 148gr wc's (page # 42.)
It states:
148gr LWC (target) 2.8gr bullseye 780fps (6" bbl) 10,000psi

I consider the 25 manual their "BEST" manual because they bought out speer after that. From then on starting with their 2008 manual they only list loads for speer bullets and no longer published pressures of their loads for pistol/revolvers. cci primers speer cases and speer bullets with a few generic cast bullets tossed. They also did away with the wc/357 target load data.
http://castpics.net/LoadData/Freebies/RM/Alliant/Alliant_2008.pdf

Myself I still use the 2005 alliant data often. Between the 2005, Hornady 4th, lyman's cast handbooks 3/4 and 5th reloading manuals and speer 12th. The only other data I use is on the hodgdon website.

 

[WestKentucky]

Others have covered it fairly well, but I will add this... light 38 loads in 357 cases may not have enough internal pressure to seal the chamber and will allow soot to get into the chambers. Also, light loads often burn somewhat dirty. The combination there can be a mess, so when I load light 357 (and I load them 1000 at a time) I load based upon the 38 loads for the bullet, and I start exactly halfway between 38 start and max loads. Crimp in the cannelure. This generally give enough pressure to shoot clean but not a whole lot of pop. I really like using 231 for that, but I haven’t stumbled across 231 in a few years.

 

[Dudedog]

I very seldom load .38, easier to just load .357 brass to the same level.
As noted about if you care about matching velocity the .357 cases take a bit more powder than the .38 cases.

but I haven’t stumbled across 231 in a few years

I see more HP38 than W231, and it is usually less money, same powder different label. (and price tag most of the time)

Not the same powder but Ramshot ZIP behaves about the same for me if you can't find W231 or HP38.

 

[Random 8]

Of the powders you mention, Bullseye and TG should be suitable. I did use TG in the .357 for light loads with a 125 cast and they were very good. In that case I simply used the same load I was loading in .38, which if I remember was already on the lighter side. I had a small batch of .357 range brass was the only reason I did this. I also tried it with unique, and they were functional and accurate but VERY dirty.

If you're trying to duplicate the velocity of your .38 loads, you will need slightly more powder to get there. While charge vs velocity is not strictly linear, so long as you're between start and max loads the relationship should be close enough for government work to interpolate a charge vs velocity approximation. You'll find Lyman cast data useful here.

 

[murf]

bullseye is quick enough to obturate everything at the low pressure you need here. I have had velocities in the 400's using bullseye and 357 mag cases. it is very consistent at low velocities.

caution: be careful you don't stick a bullet in the barrel.

luck,

murf

 

[roscoe]

Much appreciated all for this - my daughters' wrists thank you. And thanks also to bersaguy. If I hadn't ordered .38 brass this morning, I would be taking you up on the swap.

 

[Arkansas Paul]

I've loaded max .38 Special loads in .357 brass with no problem.
I've never tried light .38 loads in .357 brass.

I love it when my daughter wants to go shooting with me. She loves to shoot .38s out of my .357 Blackhawk as well.