357Mag load advice needed

Wildbillz

Wildbillz

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Joined
Apr 10, 2010
Messages
1,098
Hi All
I am getting ready to load up some 357Mag ammo. I have a box full (700 or so) Montana Gold Bullets they are a 158grn Jacketed HP bullet. I have a bunch of AA#9 powder that I would like to use. The two manuals I have (Speer & Hornaday) list loads from 9.7grn up to 13.7grn One manual says to use SPMP the other list SSP. Both manuals list loads for their bullet (Gold Dot and the XTP) not a generic 158grn JHP.

So I am thinking that I would start out at the lower end. Start at 10 to 10.5 grn. Anyone see any error in what I am thinking? The ammo will be shot out of mostly 4" guns with one 6"er. Not looking for super heavy rounds just somthing I can shoot at the range and enjoy.

Thanks for your thoughts
WB
 
I mostly use spp. I have had much better results loading to the middle of the load data. When I load at the low end I usually get lots of soot . When I load to the top end I get loads that are a handful and sometimes not fun to shoot for plinking/fun time/practice.
 
My Lyman 50th edition manual has 357 Magnum suggested starting grains of 13.4 for Acc. #9 powder behind a 158 gr. Jacketed HP, and a SPMP. That's where I would start.
 
I have run lots of Quickload (QL) stuff for 357 Magnum comparing to published loads. Things get tricky and substituting bullets can change predicted pressures a lot. This primarily has to do with bullet length and COAL variations that result in different seating depths. Case capacities can also vary from brand to brand which does not help consistency in published data.

The Hornady 158 XTP is in the Hodgdon on line tool with a 13.8 gr of AA 9 as a max. I checked, and found that this is actually taken from old Western data. My 5.0 edition of the bulletin has this listed as being tested in a 6" barrel with WSPM primers and a 1.580" COAL. They show a 12.4 gr start load. The 13.8 gr load shows pressure right at SAAMI MAP, 35,000 psi.

When I run this through QL, I get 35,324 psi with only 13.5 gr. So QL looks "safe to use" for this specific bullet / powder combination based on published data from Western. You may be ok at up to say 0.35 gr above what QL indicates, but I would not go there for regular shooting.

QL says the XTP bullet is 0.659" long giving a 0.369" seating depth.

Note that actual velocity is likely to be below predicted by ~50 fps due the cylinder gap.

Code: 
Cartridge          : .357 Magnum (SAAMI)
Bullet             : .357, 158, Hornady HP/XTP 35750
Cartridge O.A.L. L6: 1.580 inch = 40.13 mm
Barrel Length      : 5.7 inch (breech to muzzle)
Powder             : Accurate No.9

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
 %       %    Grains   fps   ft.lbs    psi    psi      %        ms
-33.3   54     9.00    918     296   13564   4471     67.5    0.848
-29.6   57     9.50    968     328   15154   4879     70.2    0.808
-25.9   60    10.00   1017     363   16907   5296     72.7    0.770
-22.2   63    10.50   1067     400   18844   5719     75.2    0.734
-18.5   66    11.00   1118     438   20978   6145     77.6    0.700
-14.8   69    11.50   1168     479   23329   6574     79.9    0.668
-11.1   72    12.00   1219     522   25913   7001     82.2    0.633
-07.4   74    12.50   1271     566   28756   7426     84.3    0.601
-03.7   77    13.00   1322     613   31883   7844     86.3    0.572  ! Near Maximum !
+00.0   80    13.50   1374     662   35324   8255     88.1    0.544  !DANGEROUS LOAD-DO NOT USE!

Now you could end up with a deeper seated bullet that will drive the pressure up. I will re-run the above pushing the bullet in 0.020" to show the impact.

Code: 
Cartridge          : .357 Magnum (SAAMI)
Bullet             : .357, 158, Hornady HP/XTP 35750
Cartridge O.A.L. L6: 1.560 inch = 39.62 mm
Barrel Length      : 5.7 inch
Powder             : Accurate No.9

Step    Fill. Charge   Vel.  Energy   Pmax   Pmuz  Prop.Burnt B_Time
 %       %    Grains   fps   ft.lbs    psi    psi      %        ms
-18.5   68    11.00   1133     450   21929   6152     78.3    0.688
-14.8   71    11.50   1184     492   24439   6577     80.6    0.653
-11.1   74    12.00   1236     536   27207   7001     82.8    0.619
-07.4   77    12.50   1289     583   30262   7420     84.9    0.588  ! Near Maximum !
-03.7   80    13.00   1341     631   33635   7833     86.9    0.558  ! Near Maximum !
 
Last edited:
Wildbillz said:
Hi All
I am getting ready to load up some 357Mag ammo. I have a box full (700 or so) Montana Gold Bullets they are a 158grn Jacketed HP bullet. I have a bunch of AA#9 powder that I would like to use. The two manuals I have (Speer & Hornaday) list loads from 9.7grn up to 13.7grn One manual says to use SPMP the other list SSP. Both manuals list loads for their bullet (Gold Dot and the XTP) not a generic 158grn JHP.

So I am thinking that I would start out at the lower end. Start at 10 to 10.5 grn. Anyone see any error in what I am thinking? The ammo will be shot out of mostly 4" guns with one 6"er. Not looking for super heavy rounds just somthing I can shoot at the range and enjoy.

Thanks for your thoughts
WB
Click to expand...
Hey Bill. I’ve seen a couple of different Montana bullets like you described. One had a conical shape nose and no crimp groove and the other had a round nose and a crimp groove close to the start of the ogive. The conical one was brassy and had a hard jacket. The round one was a lot like a Remington Golden Saber but with a straight shaft instead of the Remington bore rider type stepped base. Can you take a picture of the bullet you have? Maybe put a caliper to it and see if @P Flados can get you some better results.
 
It will depend on the velocity level you wish to reach. Most powders in the mid range shoot cleaner at 15,000 psi, and above. If the recommendation of Magnum primers is not a cast in stone thing from several manuals, Standard primers probably will do as well. Patrick Sweeney, a Guns and Ammo editor, in his first reloading manual suggested when going from a .38 Special load to 357 Magnum, simply add 10% to a top end .38 load. Adding 5-10% to a .38 +P load will often almost reach a starting load of the 357. Sooo, it's possible to load the Magnum from mild to wild, whatever your choice may be. Enjoy, and stay safe!:)
 
Last edited:
Well Lyman lists a jacketed bullet up to 14.9 that I recommend you avoid.... my load is 14.2 with an everglades 158 and that is more than plenty. Load data for #9 in 357 is all over the place. My cast load with a 156 as weighed bullet is 13.7 I seat 357 to 1.585 almost exclusively as my colt has a short cylinder.... the loads below 12 became erratic with es over 80....
 
I've only used #9 in 357 Mag once. It seemed to be erratic with the bullet/case/primer combination I was using. Historically I've seen 357 Mag data from Accurate/Western change over time with Mag versus Std primers.

The data from Lyman and Hornady seem fairly close, and are similar to Sierra and Western as well. The Hornady data is an outlier.

If I were to work up a 357 #9 load (I won't be based on previous results), I'd start with the lowest starting load among Lyman, Speer, Sierra, or Western/Hodgdon that uses the primer type I'm using (std or mag).
 
Last edited:
I use 2400 for full power .357 Mag, it simply worked and played well with others better than AA #9, for me. Looking back I should have tried a mag primer, if I didn't, I'd have to go look it's been so long. That said, AA #9 will surely work, plenty of folks use it. I'd be tempted to use a mag primer, or at least not a mild one. It likes the top end of data doesn't like to be downloaded much.
 
Just for the record Hodgdon lists magnum primers for all their .357 loads. The say "just because we know someone will". So you sorta have to decide with Hornady data. I use which ever primer I feel appropriate for the load.
 
Bill M. said:
Just for the record Hodgdon lists magnum primers for all their .357 loads. The say "just because we know someone will". So you sorta have to decide with Hornady data. I use which ever primer I feel appropriate for the load.
Click to expand...
Back when, Winchester warned against not using mag for 296 , also 748 and 760. Tad bit of old history.
 
Wildbillz said:
Hi All
I am getting ready to load up some 357Mag ammo. I have a box full (700 or so) Montana Gold Bullets they are a 158grn Jacketed HP bullet. I have a bunch of AA#9 powder that I would like to use. The two manuals I have (Speer & Hornaday) list loads from 9.7grn up to 13.7grn One manual says to use SPMP the other list SSP. Both manuals list loads for their bullet (Gold Dot and the XTP) not a generic 158grn JHP.

So I am thinking that I would start out at the lower end. Start at 10 to 10.5 grn. Anyone see any error in what I am thinking? The ammo will be shot out of mostly 4" guns with one 6"er. Not looking for super heavy rounds just somthing I can shoot at the range and enjoy.

Thanks for your thoughts
WB
Click to expand...
I went and measured my 158 gr XTP bullets, and calculating from Hornady load data, they appear to be seating the bullets at .355”, Hodgdon appears to seat their bullets at .370”, and from an older Speer manual, they appear to seat at .360”.

The three manuals were close on case length. Hodgdon lists 1.285” while Hornady and Speer list 1.290”. When I use unknown bullets, I use the measurements from known bullets to calculate the bullet seating depth, and make sure I seat my bullets to the same depth if I am concerned about pressure. Sometimes I also have to calculate the difference in published case length and my case lengths to get as close to the published load as possible. And as always work your way up.

As far as primers, I would use whatever primer is listed in the manual you are using.
 
I don't get it . If you seat to the middle of the cannelure and don't use max load how can you not go wrong.
I seat till my finger nail can just catch the grooves. Max max max . Just don't see the attraction.
 
I noted several things this morning after my post last night

First and foremost:

Wildbillz said:
Not looking for super heavy rounds just somthing I can shoot at the range and enjoy.
Click to expand...

Next, SW Heavy Pistol is a Lovex Powder (D037.2) made in the Czech Republic. I am pretty sure this is actually the same as the original AA #9 and was likely used in working up the published Western load data. AA#9 production eventually got moved to St. Marks in Florida, but they tweaked the formula to keep the old load data. If some of the published data from Lyman or the bullet makers used the St. Marks version, it might explain some of the data spread we are seeing.

The above is interesting as I use Heavy Pistol for my 160 gr Cast bullet lever gun load. I love it and found the stuff to be not at all finicky like H110. It seems to perform a lot like the un-obtainable 2400.

And last, if this is the bullet, they seem fairly typical based on the photo at https://www.evergladesammo.com/mg-38-357-158gr-jhp-bullets.html

Ok lets start with these tid bits:

- SW has Heavy Pistol load data with: 158 gr Hornady XTP 1.580 COAL, 10.0 g start, 12.1 gr max , 1296 fps and a mild 32,726 psi
- My lever gun likes a load of 12.8 gr Heavy Pistol under a 0.655 long 160 gr WFN cast bullet loaded to 1.582" (0.363" deep).

It is worth noting that the "all over the place" description has merit. The Western data has a start load (12.4 gr) that is above the SW max load. There is Lovex data out there and it is closer to Western data for max charges, but this was tested to European methods with crazy high pressures. The QL predictions seem to be "in the middle" compared to published data (a nice thing).

Regardless, lets move on and get down to some practical stuff. The crimp groove on the MG bullet will determine seating depth. There will be a very limited adjustment range (say 0.020"). Measure from the bullet base to the groove (mid point of the groove is least deep and top of groove is deepest). Everything I have looked at says you will be able to seat less than 0.389" deep (second QL table from above).

At up to 0.389" deep, the 12.5 gr / 30,262 psi prediction from the second QL table looks to be a good limit for "not super heavy, just shoot at the range". Starting at 10 gr sounds good and I would use my "stoutest" gun for initial workups. Based on my own workup with HP, I am betting anything over 11.0 gr will be clean burning and will feel like a true magnum load.

If seating depth is less than 0.360", I would push my recommendations up by say 0.5 gr.
 
Last edited:
#9 is a good powder for top-end loads in Magnum handgun cartridges. As you move further away from the top end, though, it becomes less than ideal. In the OP's shoes, I would start at the low end, but work my way up with the intent of stopping at or near maximum loads. I'd also want a chronograph, to keep an eye on SD - #9 can give consistent results, but can also give wildly inconsistent ones, especially as charge weight varies. I suspect that Magnum primers help at least a little, but don't have the numbers to back it up. Basically, I treat #9 like "H110 Lite" - it's not nearly as demanding, but it still displays a few of those tendencies.

Short version: any #9 book load and any primer should be safe, and the results should make holes in the targets. If the OP just needs to kill tin cans and cardboard silhouettes, he's on the right track. Anything more demanding than that, though, may require a bit of experimentation.
 
I am going to second Poper on this subject. My advice is to buy the latest reloading manual by Lyman and then another from someone else to get more load data and stick with what you find in them. That is what I have done since the '60's and never had even a pierced primer. Leave the experimenting to professionals with the equipment to do it safely. I have accumulated a stack of mostly obselete loading manuals now but it's interesting to compare the old data with the new. Some powders remain the same while others change and powders are made today that weren't in years past so stay up to date.

The Lee manual has a lot of data but mine is old and was just what was found in other manuals with some popular powders left completely out. I considered it to be a so-so manual for that reason and the fact that it tried to fall apart.
 
Wildbillz said:
Hi All
I am getting ready to load up some 357Mag ammo. I have a box full (700 or so) Montana Gold Bullets they are a 158grn Jacketed HP bullet. I have a bunch of AA#9 powder that I would like to use. The two manuals I have (Speer & Hornaday) list loads from 9.7grn up to 13.7grn One manual says to use SPMP the other list SSP. Both manuals list loads for their bullet (Gold Dot and the XTP) not a generic 158grn JHP.

So I am thinking that I would start out at the lower end. Start at 10 to 10.5 grn. Anyone see any error in what I am thinking? The ammo will be shot out of mostly 4" guns with one 6"er. Not looking for super heavy rounds just somthing I can shoot at the range and enjoy.

Thanks for your thoughts
WB
Click to expand...
AA9 is a bit too slow to run at low pressure. I would start at the mid-point of Western Powder's 158gr lswc data - 11.5gr and see how you like it.
There's just not much gained by starting with the starting load when using a slow powder like AA9 imho.
If you want to go slow, pick a faster powder.
 
dla said:
AA9 is a bit too slow to run at low pressure. I would start at the mid-point of Western Powder's 158gr lswc data - 11.5gr and see how you like it.
There's just not much gained by starting with the starting load when using a slow powder like AA9 imho.
If you want to go slow, pick a faster powder.
Click to expand...
Or a heavier bullet.
 
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