.357 Magnum and 2400 Powder


June 16, 2007, 02:41 PM
Earlier this year I purchased my first 1 lb. canister of 2400 powder to try some different loads in my .357 Mag. Previously I had used 296 and HS-6 with CCI-550 primers (small pistol magnum primers). The loading manual I followed was Nosler #4 published in 1996. The minimum load for a 158 gr. bullet is 11.3 grains of 2400 using Winchester Small Pistol Magnum Primers (WSPM) showing a velocity of 1480 fps. The maximum load shown is 12.3 grains of 2400 with WSPM primers at a velocity of 1520.

I loaded 10 rounds each of 11.4 grains, 11.8 grains, 12.0 grains and 12.3 grains with CCI-550 mag-primers. My intention as always was to work my way up the ladder and see how the different loads shot, stopping short of the maximums if signs of pressure showed up and unload the hotter rounds if need be. In the past, most of the hottest rounds listed in manuals did not have significant pressure signs on my .357 mag and that is why I went ahead and loaded the hotter rounds with the intention of working up to them if the lesser rounds looked ok. I had each load clearly color coded on my loaded bullets' primers.

Now I'm told that the current 2400 powder has a different burn rate than the 2400 manufactured when Nosler's # 4 manual was printed. I am also told that I should be using regular small pistol primers instead of the magnum primers.

After looking at more current load data, it does appear that most loads for the .357 Mag and 2400 powder use non-magnum primers, but more powder.

Does anyone know if these lesser loads of mine appear to be too hot with mag primers and the newer 2400 powder or do they appear to be ok to shoot?

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The Bushmaster
June 16, 2007, 04:21 PM
I have to assume that you are using a 158 grain JHP...Right? If so my Lyman 48th Edition lists 2400 starting charge at 11.3 gr. (940 fps) and maximum charge at 14.9 gr. (1280 fps) using a CCI 550 primer. My Sierra V edition 2nd printing manual lists 14.0 grains (1200 fps) and 15 grains for a top charge (1250 fps). I find that my Alliant load data manual lists 15.2 gr with a listed 1535 fps, but I doubt you'll get it in the real world. I list in my load log a 15.0 gr loading of 2400 at 1330 fps from my Ruger Blackhawk 6 1/2" barrel with a 158 grain SJHP Remington bullet using a CCI 550 primer. And that showed over pressure signs of sticking and ballooned cases.

Yes...You can use standard primers with 2400, but I don't. I would not use standard primers with W-296 or H110 either.

Be careful when working up to these higher powder charges. They can get you into trouble if you are not aware...

June 16, 2007, 10:06 PM
Yes, I'm using 158gr. JHP & JSP. Sorry I forgot to mention that.


June 16, 2007, 10:39 PM
I've never used magnum primers...ever. If you are going to use them, be sure to use data that was developed with them. Work up slowly...all of the usual disclaimers apply.

BTW, 2400 is great for magnum applications. I honestly haven't used the other powders for magnum loading because I've never found the need.

Brian Williams
June 16, 2007, 10:58 PM
I use 14.2 gr with 158Gr LSWCGC, makes for a nice load, not Mag Primers.
I now use Lil'Gun.

Steve C
June 17, 2007, 02:58 AM
The current Speer #13 manual says not to use magnum primers with 2400 as you will get higher pressure. While the Nosler data you list is pretty mild loadings it is probably correct if using magnum primers, esp. the Winchester SPM as they are probably the hottest small pistol primer manufactured today. Years ago I used magnum CCI primers as recommended in the Speer #9 but got pierced and cratered primers with loads of 13.3grs of 2400. Max load listed in the manual was something like 14.8 but I don't have access to my manuals right now.

The burn rate of 2400 hasn't changed and the current loads listed by Alliant match 25 year old data that Hercules published. However primers have changed and 2400 was never a hard powder to lite off.

My current 158gr load using either a Remington or Winchester bulk bullets is 14.0 grs of 2400 with a CCI 500 Standard small pistol primer duplicates factory loads and chrono's at 1,243 fps from my 4" S&W M66.

June 17, 2007, 03:18 PM

June 17, 2007, 03:21 PM
Since current load data does not recommend using magnum primers, I believe I will go ahead and unload the cartridges in question and reload them without mag primers. I was actually trying to use up all of my CCI 550 primers with the intention of switching to WSP primers in the future.

Thanks for the responses guys, I appreciate it very much.

June 20, 2007, 11:27 PM

I understand you are now using Hodgdon's Lil' Gun for your 158gr reloads.

I want to be sure to use data that was developed with the proper primer.

Hodgdon does not list a primer requirement on their Data Center.

Does Hodgdon's Lil' Gun require small pistol magnum primers?


June 21, 2007, 05:30 AM
I'm using either H110 or W296 for my .357 Magnum rounds. Both recommend Magnum Primers. I find that these powders when pushed to the max load are very hot loads and work well in my Marlin Carbine. I use 16.7 gr of powder to push a 158 gr FMJ bullet and drop the charge to 15.7 gr for my pistol using the same bullets. I've been using Winchester Small Pistol Magnum Primers.

June 21, 2007, 06:11 AM
I use magnum primers with 2400 and 158 grain SJSP bullets ... see


the Alliant web page ... it shows Federal 200, a magnum small pistol primer and 14 grains maximum for 2400 powder. I've always understood it that the magnum primer amounts to about .1, or .2 gains of powder. I usually load mid range, so 13.3 grains 2400, with magnum primers, and get about 1150 fps in my 4" S&W 686.

June 21, 2007, 07:13 AM
I load 18.5 grains of 296 with a 125 gr JHP. Makes a nice boom, and very accurate, no signs of excessive pressure.

June 21, 2007, 08:35 AM
Hodgdon's FAQs say that magnum primers are appropriate with H110, LilGun and Longshot. The tables don't indicate their use, but Hodgdon's tables are a pipe dream anyway.

Brian Williams
June 21, 2007, 10:30 AM
I use regular primers. This load works for my 1894C very well and I have only used it a little in my revolvers.

June 22, 2007, 01:55 PM
2400 + std primer + 158gr LSWC = good shootin'

Here is my experience with those compnents:

tasco 74
June 23, 2007, 01:56 AM
when i got my reloading press and stuff from bro in law one of the rotors for the powder measure said 16 gr. 2400.......... that really seemed like a stout load so i didn't load mary of them..... the revolver i had at time was a s&w mod 13 4" and i was afraid to stretch the frame on it..... i never got the chance to chony a 158 gr bullet with that charge for sure but i bet it was fast...........

June 23, 2007, 09:48 AM
I use WSP primers with 2400 behind a 125 hornady XTP with good results, of course I live in Florida and do not have to contend with cold weather either. If it gets real cold were you live magnum primers might make more sense.

Bad Flynch
June 23, 2007, 11:44 AM
If it makes any difference, the maximum pressure for the .357 Magnum has been lowered over the years. In the late 1960s, I shot a Colt SAA in .357 Magnum. I used, the (then) recommended load of 15 grains of 2400 under a 158 grain semi-jacketed bullet. Hot load, much noise, much muzzle blast. Luckily there was a lot of metal in that Colt's cylinder.

However, the smaller frame .357s, like the K-frame S&W, had trouble with those hot loadings (and factory fodder, too). Typically, they would spread the back end of the barrel out and loosen up prematurely. Some time in the intervening years, SAAMI dropped the MAP by about 10%. That means that older data is not correct by modern standards.

I have been told that Alliant/Hercules dropped the percentage of Nitroglycerin in their powders at some time over the years, too. That means lower energy content, overall.

If you have one of the lighter-framed .357s, then take it easy on the thing, please. If you have a Ruger, then you have a little more leeway.

June 23, 2007, 11:51 AM
I wish to load 357 caliber using S&W 2 inch and 6 inch revolvers with 125 gr jacketed bullets using Winchester 296 ball powder.

Has anybody done this and what charge do you use?

I have gone to the Winchester web site and reviewed their data. They recommend starting load of 21 gr and maximum load of 22 gr

I appreciate any information you might have


Bad Flynch
June 23, 2007, 04:24 PM
Cal 44,

>I wish to load 357 caliber using S&W 2 inch and 6 inch revolvers with 125 gr jacketed bullets using Winchester 296 ball powder.<

I can think of better powders for snub nosed revolvers. H110/WW296 will not burn well in a snub-nosed revolver. Even in a long barreled gun, they usually produce lots of muzzle flash and unburnt powder. Lil'Gun isn't much good, either.

I suggest you look for a one step or so faster powder, like 2400 loads, upper end Unique loads, 4227 loads, etc. A slightly faster powder with the light bullet will burn better and, will burn more completely in a short=barreled revolver. The same loads will burn fine in the 6 inch revolver.

June 24, 2007, 11:38 PM
I use W231 or HP-38 for .38 Special rounds. When I load .38 Special +P I switch over to Longshot powder because it generates greater speeds than the previous powders at a lower pressure. When I load .357 Magnum rounds I use W296 or H110 because they are designed to burn slower and generate the proper speeds without exceeding the pressure limits.

W296 and H110 require Magnum Primers.

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