Trying to develop an "entry" level 357 Mag load at 1,200 fps with 158 gr SWC and 2400 in 6 inch barrel. Absent chronograph and using some Speer data, I come up with approximately 12.5-13.0 grs of 2400.

What would be some of your recommendations?

Thank you,

Eric

According to Alliant online manual it takes 14.8 gr of 2400 for 158 (GDHP) bullet to cross 1200 mark (they list 1265) out of 10" test barrel (which doesn't have b/c gap). I'd invest in chronograph, start at the load you've specified and push it up till you satisfied or pressure signs show up.

Check posts.threads from forestswin he did lots of 2400 and 158 gr loads.

You might say he is obsessed with it! Don't forget to trim that brass!!

forestswin

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Still Running Against the Wind

Looking for 158 gr lead SWC. My range does not allow chronographing, space limited

Thanks Rule3

Is your 158 gr. SWC lead or jacketed? Makes a difference, sometimes a big difference.

I've used 13 grs. #2400, CCI standard small pistol primer, and a 160 gr. SWC cast of wheelweight alloy from a Hensley & Gibbs #51 mould. Fired from a 6" barrel, I've chronographed this load at 1160 fps muzzle velocity. Another 1/2 grain of #2400 should put it right at or very close to 1200 fps.

You might be in a very high pressure situation pushing until pressure signs show up, especially with handgun ammo.

I can't find any Speer data that gives loads that drive a 158SWC to 1200fps. And none using 2400 powder.

This kind of extrapolation, using a very different bullet, very different barrel, without a chrono, or even with one, is very dangerous IMO. Stick with published loads.

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USAF, 69-92
Vietnam, 72-73

Lyman #46 shows a 155gr lswc # 358156
10.6 gr 2400=999fps-14.0 gr 2400-1299fps

Old Speer data shows their 158 gr. LSW and 13 grs. #2400 giving 1235 fps MV using a CCI magnum pistol primer. Fired in a 6" Mod. 27. Standard CCI primer should give about the same velocity, maybe a little less.

What # Speer are you using?

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USAF, 69-92
Vietnam, 72-73

I agree with Rockquarry. 12.5 grs of 2400 probably is a bit light and will not be very uniform or very clean. Increasing to 13.5 grs or so will help with those things and get you pretty close to 1200 FPS in a 6-inch gun. (This is assuming that when you say "SWC" you mean a lead semi-wadcutter of some sort.)

I have never seen a big need for magnum primers with this load and have always used Federal 100s. It is a good .357 load that has always been very accurate for me and seems to be easy on the guns. It is about as much as I care to shoot in a K-frame .357.

(Customary disclaimer) This is just my experience so of course you need to do your own due diligence with published data-working up-etc.

Speer #6, #7, and #8 all have similar data.

I'm aware of #8's cautionary reputation, but 13 grs. #2400 with a 158 lead SWC should be quite safe in any .357 revolver that is in good condition. Load might be prone to leading if the bullet fit is a bit off.

I don't waste my 2400 on lead bullets for 1200fps loads .........

since I can reach those figures with Unique powder or HS-6.

However I will use 2400 in all my copper jacket 158gr bullets.

If you have more than a pound of it, no problem......
and those figures you have should get you close to 1200fps in a 6" barrel if it is tight.

Maybe I'll scrap the idea of 2400, I have a little left and will just use that in a load developed years ago but in 38 cases - 11 grs with 158 gr SWC. Only used in 357 Mag, probably gets me in 1,100 fps range, and it has proved very accurate in my revolver.

After that, I'll just stick with Unique mid range loads (1,000 - 1,100 fps) and use factory loaded 357 Mag for my magnum loads.

...my other favorite load in 357 magnum is 6.0 grs Unique and 158 gr swaged SWC (357 Mag cases) - very accurate. Probably about 1,025 fps. Good mid range load.

38spl HV
don't give up!

as far as I'm concerned 2400 and 357 mag
is one of top load combinations that I've shot for all calibers

all charge weights are less than max - (15.3 gr) (older Alliant Manual)

I shoot these loads in a S&W 686 6 inch 357 magnum
magnum primers will give you about an extra 50 fps - but std primers are fine

very accurate

you're probably looking at a 13.2 grain load

go through some of my range reports from here in S&W forum - links below:
I've given all the details in charts or on the targets - and many members here helped me along giving me great advice in my thread -



Chrono data 357 / 2400 / CCI500 / 158 gr cast w/targets

Chrono data with target groups +

Chrono data 357 / 2400 / CCI500 / 158 gr cast w/targets

Range Report Bayou Hi-tek coated 158 L SWC and 2400 in 686

send me a pm if you want anymore data

I'm told - By a elderly gunsmith, that all 686's have tight barrels
mine is 0.3565" throats are .3570"

also see my Unique data threads also
158 swaged bullets - is the other best load combination

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I'd like to agree with you BUT

Thank you Rule3, great inputs and advice!!!

Forest deserves the praise, he did the work. He likes that kinda stuff. He goes to the range with chronographs, computers,scopes, notepads spotters, range finders (so he can find the range) and spotting scopes,

Me I just like to shoot. It gets so hot and humid here I don't even want to set up the chronograph!

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Still Running Against the Wind

According the the Lyman 4th Edition Cast Bullet Handbook a lot if the above advice is spot on.

According to the Lyman data published in 2010 a charge of 13.5gr 2400 under a 158gr Lyman #358665 cast bullet your velocity will be 1275fps. This was measured in a 4" Universal Receiver. The results in your revolver will most probably top 1200fps, exactly what you are looking for.

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Freedom is never free!!
SWCA #3437

Just two final comments:

- For the 158 SWC, 1200 fps is a bit much.

- But if you must, then Unique is a better choice than 2400. It's in the 6 + gr. range vs. 13+ gr. Half as much powder for the same zip. Save the 2400 for real magnum loads.

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USAF, 69-92
Vietnam, 72-73

Thank you forestwin, I misread who posted the great data, my apologies ("senior" moment for me!)

You have some excellent information!

Thank you

You're welcome. Hope it helps. Please post your findings when done.

Actually, some thanks should go to Rule, he helped me tremendously as I started out.,so did many others here.

But Rule hates making spreadsheets and charts and the like.
They're Indiana's snakes and Henry's rats to him.

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I'd like to agree with you BUT

Eric,

I don't have any loads that match just what you are looking for, but using some data I have chronographed, and doing a bit of interpolation, I would expect to get 1200 +/- FPS from a 6" .357 with 12.9-13.1 gr. 2400. Naturally this can vary a bit gun-to-gun. This result was averaged from three different trials of three slightly differing loads shot in a 6" Highway Patrolman, all with a 158 gr. LSWC.

And for who posted: "For the 158 SWC, 1200 fps is a bit much," Maybe you should stick to commenting on a subject you know something about! 1200 FPS from a 6" .357, with this load combination, is really a fairly moderate load!

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Gunsmithing since 1961

13.5 gr of 2400 with a Oregon Trail 158 gr LSWC using magnum primers gave me 1150 fps in a 4 inch model 66. It's all I'd want to shoot !!

"And for who posted: "For the 158 SWC, 1200 fps is a bit much," Maybe you should stick to commenting on a subject you know something about! 1200 FPS from a 6" .357, with this load combination, is really a fairly moderate load!"

Why the attitude?

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USAF, 69-92
Vietnam, 72-73

Well here we go again, same old stuff, different day. The 38 spl or
357 mag, opinions, fears etc and lots handloaders who think they want
full 357 loads until they try them and then quickly change their minds.
Why doesn't every handloader own a chronograph? Anyway here is
some data from my chronographing of the 357 in my back yard where
I don't have to deal with range rules, all with 158 gr cast SWCs.
All loads chronographed from a 4" S&W 28-2. With 2400 powder,
12.0 grs, Win mag primer vel=1228 fps ES=13 fps, 13.0 grs, Win std
primer vel=1144 fps ES=130 fps, 14.2 grs Win std primer vel=1208 fps
ES=34 fps and this is why I use mag primers with 2400 in the 357 and
now have decided to use mag primers with all 357 loads. 1200 fps is
easily reached with 158 gr cast SWCs without pushing the loads in
a 4" barrel. Try this load, 7.9 grs Longshot, 158gr SWC, Win mag
primer vel=1200 fps, same with small rifle primer vel=1198 fps. This
is from a 4" barrel and it's been awhile since I have chronographed
from my 6" mod 28-2 but loads with around 15.0 grs 2400 and a mag
primer = over 1400 fps. Yes 1200 fps with a cast SWC from a 6"
barrel is a fairly mild load. It's just that many handloaders
these days aren't used to full 357 magnum loads.

Actually, HS-6 will work better than both those powders but the OP specifically asked about 2400. That's why I posted the data from the Lyman Cast Bullet Handbook.

Anywhere between 9.5gr to 10.0gr HS-6 will get you there depending on the bullet you're using. I use HS-6 for middle to middle hit .357 Magnum loads especially with lead bullets.

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Freedom is never free!!
SWCA #3437

Using Ideal #357446 SWC, crimped in middle groove, 12.5gr 2400 in .38Spl WCC +P+ brass, I recorded 1158 fps from 3" sp101, and 1219fps in 4" 686. Now then, the air space under the bullet seated long is pretty close to the space under the same bullet seated to crimp groove in a 357 case, so results should be similar. This load is one that Skeeter Skelton used many winters ago.

As an aside, ES was 16, SD was 5.

I'm assuming the OP is using hard cast bullets, not the swaged variety that are very soft.

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"He was kinda funny lookin'"

Thank you all!

12gr of 2400 with a cast 158gr swc is a most accurate and satisfying 357 load, especially out of a model 19 snub.

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Where we go one, we go all

Sometimes,little things make a big difference.While I shoot full bore 265gr .44 Mag acurately for 50rds(offhand at 20yds in a 4 1/2 '' black with aprox 45shots in it)I must admit that a K frame .357 with full house load is also a handfull.I've had a custom grip made for my DW.44 and,if I could affford it,I'd have the same done for some of my .357.A grip that fits makes a world of a difference.
I've shot the load you describe and let me tell you Sir,in a K frame,yes it gets your full attention when you touch one off!