.357mag, 2400, 158gr Cast SWC

[roo_ster]

I did some min-max loads with this combo & this is the second iteration.

The choice was between 15.2gr & 15.3gr (max).

I recall some other poster saying that 158gr LSWC & 15.2gr of 2400 was the bee's knees for his .357mag. I guess I could have saved myself some time. But, you never know until you try it out in your gun.

These loads are stout, but don't seem too hot. Recoil is not too bad. I contrast this with some factory .357mag with 158gr pills. Some of that stuff is hothothot and the muzzle blast is more significant.

These were shot from the seated position, uncomfy pole against my back, with elbows on knees.

Cartridge           .357_Magnum                .357_Magnum
Date                2005-10-04                 2005-10-04
Wpn_Manuf         Smith & Wesson             Smith & Wesson
Wpn_Model               686                        686
Wpn_BBL                  4                          4
Bullet_Manuf          Rucker                     Rucker
Bullet_Const           Cast                       Cast
Bullet_Profile          SWC                        SWC
Bullet_Wt               158                        158
Bullet_Base            Bevel                      Bevel
Bullet_Diam            0.358                      0.358
Powder_Manuf          Alliant                    Alliant
Powder_Name            2400                       2400
Powder_Wt              15.2                       15.3
Primer_Type             SP                         SP
Brass_Manuf         Winchester                 Winchester
Brass_Trim_Lengt        NA                         NA
Crimp                 Roll_H                     Roll_H
Group_Size               8                        10.6
Group_Num_Shots         16                         14
Group_Dist              25                         25
MOA                 30.55774907                40.48901752
MOA/Shot            1.909859317                2.89207268
Comments        Little unburned powder     Little unburned powder

 

[Stinger]

15.2 is a minimum load???

Not that I have ever seen...

Be safe,

Stinger

 

[roo_ster]

15.2 is a minimum load???

Not that I have ever seen...

Be safe,

Stinger

I did some min-max loads with this combo & this is the second iteration.

I had already gone from manual min-max in a previous iteration in some step (somehting like .2 gr inervals). The max load (15.3gr) had shown best results, accuracy-wise. I wanted to be sure I wasn't missing some sweet load between 15.1 & 15.3, so I decided to back off .1 grain & test it. Turns out that 15.2 wa a bit better.

 

[Ben Shepherd]

It may have been me- my 357's are pushing upwards of a collective 100,000 of those loads. That IS my all purpose 357 load.

Wanna try another?

Try 14.8 grains of 2400 under a 158 gr. speer gold dot. Works well.

 

[Hook686]

What kind of velocity do you think you are sending those cast lead bullets ? I was told that with lead bullets the velocity ought be kept below 1000 fps. I'm thinking 15 grains of 2400, aside from being perhaps over pressure, might be above 1200 fps. I'd be concerned not only with pressure, but leading my barrel and adding to the pressure concern.

Well good luck to you.

 

[roo_ster]

Oops! DUH-ble Post

Nothing to see here.

 

[roo_ster]

Hook686:

I got 1438fps with 15.3gr of 2400 (max load) in warm weather. I expect 15.2gr to be slower.

These are hard cast LSWC, so I 'spect they can be pushed faster than their swaged brethren.

I did note some light leading with 15.3gr & a little bit of unburned powder on my first interation (13.5gr-15.3gr). By the time I got to 15.3gr, I had already shot 50 or so rounds on an originally clean bbl. Five stroked with a dry bronze brush eliminated any leading that I could see with a naked eye.

On my second interation (15.2gr-15.3gr), I noticed no leading and even less unburned powder with either 15.2gr or 15.3gr. I started with a clean bbl.

I am not sure how much leading would occur over an exended shooting session. I think that is my next step: load up a bunch & shoot them off.

Pressure seemed not to be an issue. When working up from minimum on the first iteration, the primers appeared "rounded" and like I wasn't getting enough pressure to get them to look like factory primers. At 15.2gr and 15.3gr, the primers looked like what I have seen on most .357mag primers from the factory.

I would note that my reloads' subjective feel, from muzzle blast & recoil, was less than from several factory brands I have used. S&B 158gr would even cause the brass to stick in the chambers of my snubby (not used in this test) and had more muzzle blast & recoil. Samson 158gr didn't stick, but had more blast & recoil.

I don't have pressure testing equipment, but the traditional signs of overpressure were absent. Also, my chrony reading of the load was in line with what the loads books said it was (if it were faster, I would suspect something was up). Add to this that I stayed within current max loads, I feel as confident as I can that my loads do not exceed what is currently considered safe pressure for .357mag. Of course, this is in MY S&W686 with MY loads.

If you want really low-pressure loads, try yourslef some Trail Boss (load data found on the TB manu website). I posted my TB results here last week & it works swimmingly in light loads. And it was cleancleanclean.

Ben Shepherd:

If you also told me to go from mixed brass to all the same headstamp, it was likely you. I DID use all the same headstamp this time 'round. Matter of fact, I now have sorted all my .357 brass by headstamp. Only a little bit remains in my "mxed" coffee can.

I intend to sort all brass in the future, though it will all still be used.

Oh, what purpose does your Gold Dot load serve that your LSWC load does not?

Index	5
Cartridge	.357_Magnum
Date	2005-05-07
Temp	75
Wind	10_45
Wpn_Manuf	Smith & Wesson
Wpn_Model	686
Wpn_BBL	4
Wpn_Serial	
Bullet_Manuf	Rucker
Bullet_Name	-
Bullet_Const	Cast
Bullet_Alloy	Unk
Bullet_Profile	SWC
Bullet_Wt	158
Bullet_Base	Bevel
Bullet_Diam	0.358
Bullet_Lube	Unk
Bullet_BHN	Unk
Powder_Manuf	Alliant
Powder_Name	2400
Powder_Wt	15.3
Powder_Filler	None
Primer_Manuf	
Primer_Name	
Primer_Type	SP
Brass_Manuf	Mixed
Brass_Trim_Length	NA
COL	
Crimp	Roll_H
Vel_Avg	1438
Vel_SD_Avg	125.05
Vel_ES	228
Group_Size	1.3
Group_Num_Shots	5
Group_Dist	10
MOA	12.43
MOA/Shot	2.49
Pressure	
Comments	Unburnt power in one chamber only  & bbl; Primer strikes more normal; Leading first 1/2 of bbl;  Dry bronze brush chambers & bbl

 

[anonanon]

1/10 of a grain might be enough to send pressures into the danger zone, but I can't see it mattering much in velocity or accuracy. There's probably more deviation (in both velocity and accuracy) from shot to shot in the same load than there is in the average of 15.2 and 15.3. That's less than 1% variation in powder weight.
Did I read your velocity chart right, that your SD for 5 shots is 125 f/s? And the spread is 228 f/s?
Did I read your accuracy chart right, that you only shot one group of 15.2 and one group of 15.3, and your group size was 8" and 10.5" at 25 yd.? But that you fired 16 and 14 shots in the group?

 

[roo_ster]

Did I read your velocity chart right, that your SD for 5 shots is 125 f/s? And the spread is 228 f/s?
Did I read your accuracy chart right, that you only shot one group of 15.2 and one group of 15.3, and your group size was 8" and 10.5" at 25 yd.? But that you fired 16 and 14 shots in the group?

Velocity
You read it right.

This particular reading was the first time I had ever used my chrony...and I clipped one of the rear rods. I didn't notice the rod-hit until later. I can not recall the exact velocity reading for the five shots, but there was one outlyer. Also, I was using mixed brass.

Nowadays I use wooden dowels instead of the rods provided with the chrony (to make it easier to see if I clip one and to prevent damage to the chrony if I make a solid hit on the rod).

Accuracy
Again, you read it right.

I did not have a bench to provide a sold rest. I was stuck in a seated position, leaning my back against an uncomfortable pole with my lower triceps resting on my knees, legs kinda splayed out. It was as solid as I could get, given the circumstances. I do not own a Ransom Rest.

With regard to the different number of shots recorded, it gets complicated.

Hold on to your hat...

For each test case (15.2 & 15.3):
1. I shot 20 rounds total.
2. One target was stapled to the backer (call it "TWENTY") which stayed put during the entire case and could theoretically show 20 shot impacts.
3. Two targets (call them "TEN_1" and "TEN_2") were, in succession, stapled over TWENTY. TEN_1 for the first 10 shots (then removed), TEN_2 for the last 10 shots (then removed).
4. Four targets (call them "FIVE_1" through "FIVE_4") were, in succession, placed over both TWENTY and one of the TEN_* targets. FIVE_1 for hte first five shots, FIVE_2 for the second five shots, & so on.
5. At the end of it all, I had:

• 7 total targets
• 1 target with twenty potential shots
• 2 targets with 10 potential shots each
• 4 targets with 5 potential shots each

Notice I wrote "potential?" Well, some shots were not on paper. Either I couldn't hold well enough, or POI shifts, or the Reloading Gods were angry with me...whatever...only 16 of the 15.2gr case and 14 of the 15.3gr case hit paper.+ The balance hit the backer, where the multitude of past shots made it impossible to tell where my off-paper shot hit.

Of course, that throws off the statistics, so I was stuck with analyzing an incomplete data set. I gawked at the FIVE_* & TEN_* targets and noticed a slight trend in favor of 15.2gr. Then, looking at the TWENTY targets, the trend was more pronounced.

I am not happy with the metric MOA/Shot, but I found it necessary to compensate for shot groups where some of the shots go off into "backer-land." You do what you can with what you got.


+ I have learned from my mistakes. I bought a big roll of butcher paper and cover the complete target backer with it from the start and then staple my targets on top of that. If a shot is not "on paper" (of the target), I note the vector to the center of the shot from a point on the edge of the target. Something like: 2", 45deg

I hope the explanation helps.

 

[anonanon]

Jf, sounds like you fired enough groups (4 ea of 5 shots) for the results to be meaningful -- but that the flyers are an indication that no valid conclusions can be drawn from the rest.
Admitedly, firing braced the way you were is difficult. I doubt I could do as well. But by the same token the results can't be taken as proof of load accuracy when the ability to hold is a much greater factor.
The range at which I am a member provides concrete tables. I made myself a rest to hold the gun and my hands steady, so they don't shake when the rest of me does. With my heavy barrel 8" Dan Wesson, my standard for accuracy is about 4". At 50 yards. Wish I could say the same for my 6" DW or my Taurus titanium 6,5". I think the lighter guns begin to recoil sooner and my hands aren't rigid enough to hold them. Wish I had a Ransom Rest too, to take the human factor out of it completely.
The thing is, I just don't think 1/10 of a grain of 2400 -- well under 1% -- is making any difference. If you tested one bunch at .5 grain less and another bunch at 1 full grain less, you might be able to see a difference.
As for velocity, glancing real quickly at a book I see that a 2 grain difference of 2400 makes a 200 f/s difference. I know it's not truly linear, but if it were that would work out to a 10 f/s difference between your 15.3 and 15.2 loads. Totally lost in a standard deviation of 125 f/s. Again, if you tested one group at .5 gr less and another at 1 full gr less, you'd be able to see a difference.
One final comment, but you probably know this. When you're dealing with pressure, 1/10 of a grain can make a difference.

 

[Ben Shepherd]

The "purpose" of the gold dot loads? I use them for CCW, actually. The HCSWC's go a little deep for that purpose.

As for velocity: out of my 7.5 'hawks the 15.2 lead load does an honest
1550 fps, leading is not an issue with the slugs I use.