125gr LRN in 357 mag

B

BoogieMan

New member
Shortages and other factors have got me locked into a combination.
125gr LRN in 357m using Power Pistol and SPM primer.
Starting mag load for 125jhp is 9g in Lyman book. I would like to be closer to 38+P levels. But, I am concerned about dropping to 6.4g with this combination.
As an alternative I have enough 231 on hand to get me through.
Can someone recommend a safe starting load? Shooting from a short barrel snubby.
 
My 2021 Hodgdon's manual for .357 with cast LRNFP, COL: 1.580"

231 min 4.6 grains Max 5.5 grains using Winchester SPM primers.
Velocity cited uses a 10" barrel with 1052 to 1185 FPS

This manual has 38 Special +P loads but none involve cast 125gr bullets or 231. The above .357 load is a bit above the standard 38 Special of 3.8 min and 4.8 max for 231 with velocities in the 870 to 1070 range.
 
I use both Win 231 and power pistol in 357 mag with 125 and 158 gr bullets
I would suggest win 231 for loads in the 38 special to 38+P range as it tends to burn slightly cleaner than reduced loads of power pistol
ballardw's data is pretty spot on for the loads you are loading.
 
Go with the 231. 5.0 to 5.5 would be my choice. I like 158 Lead and 5.5gr 231 in 357. 4.5 in 38 special cases. Air space is not your friend with these cartridges so down loading a dense ball powder would be my last choice. 231 may be less case sensitive overall.
 
Definitely use 231 for mid range.

I have a Hodgdon pamphlet that shows a 38 Sp load for a 125 bullet as low as 4.9 gr 231. The 357 mag load for a 125 is 8.5 gr. Anything in the middle of this range should be safe for a 357. However, the Hodgon data is not much use to you for velocity with your short barrel.

My Quickload (QL) software is not accurate for pressures, but is pretty good for estimating velocities. In a QL, the barrel length is from breech to muzzle so I guessed at 3.6" for a snubbie.

The chart below shows 5 gr gives you 832 fps and 8 grs gives you 1180 fps. Mid range would be real close to the 6.4 grs and 1006 fps prediction.

Cartridge : .357 Magnum (SAAMI)
Bullet : .356, 125, LEE 356-125-2R
Useable Case Capaci: 18.756 grain H2O = 1.218 cm³
Cartridge O.A.L. L6: 1.590 inch = 40.39 mm
Barrel Length : 3.6 inch = 91.4 mm
Powder : Winchester 231

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.857% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-28.6 38 5.00 832 192 13248 6163 97.0 0.595
-25.7 40 5.20 858 205 14224 6442 97.8 0.573
-22.9 41 5.40 884 217 15237 6712 98.5 0.553
-20.0 43 5.60 910 230 16288 6972 99.1 0.533
-17.1 44 5.80 934 242 17377 7223 99.5 0.515
-14.3 46 6.00 959 255 18505 7463 99.8 0.498
-11.4 47 6.20 983 268 19671 7691 100.0 0.483
-08.6 49 6.40 1006 281 20877 7908 100.0 0.468
-05.7 50 6.60 1029 294 22122 8120 100.0 0.454
-02.9 52 6.80 1052 307 23407 8331 100.0 0.441
+00.0 54 7.00 1074 320 24733 8542 100.0 0.428
+02.9 55 7.20 1096 333 26101 8752 100.0 0.417
+05.7 57 7.40 1118 347 27510 8961 100.0 0.406
+08.6 58 7.60 1139 360 28962 9171 100.0 0.395
+11.4 60 7.80 1160 373 30457 9379 100.0 0.385 ! Near Maximum !
+14.3 61 8.00 1180 387 31996 9587 100.0 0.376 ! Near Maximum !

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 54 7.00 1102 337 27716 8395 100.0 0.404
Data for burning rate decreased by 10% relative to nominal value:
-Ba 54 7.00 1033 296 21587 8690 99.5 0.460
 
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For those of us who don't use that program and are not well trained in its abbreviations, categories and what they mean, your table, though well intentioned, is just a useless jumble of numbers.

One point I would make, about .38 and .357 case volumes is that while the .357 case is 0.135" longer than the .38Spl case, the max loaded length of the rounds is 1.590 vs. 1.550". Using the same bullet, seated to max length, that makes the .357 capacity a cylinder 0.04" longer than the .38 Special.

That is NOT a lot of difference. It's less than the thickness of a dime.
 
44,

All of the forums seem to run software that makes a mess of tabular data. I have tried to clean up this kind of stuff before, but it does not seem to be worth the effort.

I usually choose a better (fixed pitch) font that helps a little but I failed to when I made the post. I went back and made the font change now.

Most people look at it, realize that if they mentally draw lines down where the spaces are it all makes more sense.

I did throw in some text explaining charge weigh vs speed for 5 gr, 8 gr and 6.4 gr. the text may help someone confirm that they have it figured out.

Again, in each line the space is a break between columns. Column 2 is case fill in %, Column 3 is charge in grs, Column 4 is velocity in fps, Column 6 is chamber pressure in psi.

I do agree with your point about the similarity of the 38 sp to the 357 mag for case capacity. It also helps that fill percentages are low (38% to 66%, see column 2) such that small changes in AOL do not make much difference in round performance. Changes in AOL matter more for rounds that have high percent fill like the 9 mm.
 
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P. Flados,

The forum software truncates all leading and multiple spaces, making tables impossible in the text body. However, it also comes with a workaround sub-window that does not do that. To invoke it, at the start of your table place the code tag and at the end place the concluding code tag. It looks like this:

[code]Your table content[/code]

The font probably won't match your spacing exactly, so I recommend you use the font tag to change the font inside the code window to one of the fixed character space fonts like Courier New or Fixedsys to make that easier. Use the review feature to see how it has lined up. Readers will have to scroll through the code menu, but it's not difficult.
 
Wow. So much better. Thanks heaps.

Code: 
Cartridge          : .357 Magnum (SAAMI)
Bullet             : .356, 125, LEE 356-125-2R
Cartridge O.A.L. L6: 1.590 inch = 40.39 mm
Barrel Length      : 3.6 inch = 91.4 mm
Powder             : Winchester 231

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
 %       %    Grains   fps   ft.lbs    psi    psi      %        ms
-28.6   38     5.00    832     192   13243   6163     97.0    0.596
-25.7   40     5.20    858     204   14218   6441     97.8    0.573
-22.9   41     5.40    884     217   15231   6711     98.5    0.553
-20.0   43     5.60    909     230   16281   6972     99.1    0.533
-17.1   44     5.80    934     242   17370   7223     99.5    0.515
-14.3   46     6.00    959     255   18497   7463     99.8    0.498
-11.4   47     6.20    983     268   19663   7691    100.0    0.483
-08.6   49     6.40   1006     281   20868   7908    100.0    0.468
-05.7   50     6.60   1029     294   22112   8120    100.0    0.454
-02.9   52     6.80   1052     307   23397   8331    100.0    0.441
+00.0   54     7.00   1074     320   24722   8542    100.0    0.428
+02.9   55     7.20   1096     333   26089   8752    100.0    0.417
+05.7   57     7.40   1117     347   27497   8961    100.0    0.406
+08.6   58     7.60   1139     360   28948   9171    100.0    0.395
+11.4   60     7.80   1160     373   30443   9379    100.0    0.385  ! Near Maximum !
+14.3   61     8.00   1180     387   31981   9587    100.0    0.376  ! Near Maximum !

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba     54     7.00   1102     337   27703   8395    100.0    0.404
Data for burning rate decreased by 10% relative to nominal value:
-Ba     54     7.00   1033     296   21577   8690     99.5    0.460
 
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