ww296 in 357 mag with cast 158 swc

[avan47]

I am trying to find the maximum safe load for my S&W Mod 19, using Win 296 powder, CCI 550 primers, and a Lee cast 158 gr SWC with GC. The boolits I currently have are WC 50/50 WW and lead. They are about BHN 13, sized to .358, and lubed with BAC. My Sierra manual lists a max load for their 158gr JHC of 17.3 gr of 296 for 1250 fps out of a 6 in barrel Colt MkIII Trooper. They also list a start load of 15.9 gr at 1150 fps, and 16.6 gr at 1200 fps. Based on this data, I tried 14.5, 15.5, and 16.5 gr and got 1137, 1221, and 1397 fps respectively. These loads were with the same boolit design, but ACWW, BHN about 11, and lubed with Alox/Beeswax. There was no leading, primers look normal, and extraction was ok. I also tried 16.0 ww296 with the WC 50/50 ww/lead, lubed with the BAC, and got 1299 fps with that load. The higher velocity I am seeing with these loads could be because of lower bore friction with the cast boolit than there would be with the JHC, or it could be because of higher pressure. I am concerned, because none of the other reloading manuals I have list charges this high for ww296. Speer lists 14.7 as max, and Hornady lists 16.0 as max, but these are for jacketed bullets. Winchester Ball Powder Loading Data lists 16.6 gr for jacketed at 1610 fps, and 39,500 CUP, and only 14.5 gr for lead bullets at 1560 fps, and 38,000 CUP. These velocities are from an 8.375 inch barrel. My question is: Can I substitute a cast boolit for a jacketed bullet without raising pressure? It seems logical for me to think that a cast lead boolit would produce less pressure than a jacketed bullet in the same load, but I am not sure. So I am seeking the advice of those who have more experience with this powder than I have.

[runfiverun]

yes.....

[stubshaft]

Are you trying to find a max load for speed only or speed and accuracy?

[Grandpas50AE]

Really good question Stubshaft. The most accurate loads I have found in the magnums when loaded near the top of the map have been approximately 90% of max.

Avan47, within certain parameters that only your gun can tell you, general rule of thumb is that Runfiverun gave you a good answer. There are so many variables that affect pressures, particularly at maximum recipe, that you really have to work up your own like the manufacturers suggest. Each gun will have its own dynamics. The differences in load data from one manual to the next will vary based on their own test firearm, and the difference in dynamice of each is why their is somewhat of a spread in their data. You are seeing why it is a good idea to have several manuals to cross-reference, since a misprint on any given recipe CAN happen (although not very often), the other manuals become an indicator of potential mis-printed data in the other. Just work up slowly and your gun will indicate ITS max.

[Shiloh]

I went with 2400 for that boolit in .357 mag.
The numbers on the chronograph were more consistent with it. Groups seemed a bit smaller as well.

I don't shoot very many anymore as I went to a lighter boolit and loads.

Shiloh

[avan47]

Speed and accuracy.

Winchester says 296 is the factory powder in the 357 magnum, but I am interested in its suitability for use with cast boolits. The manuals don't seem to give much leeway for working up a load with 296 as it seems to have a very narrow working pressure. I am most interested in not causing any damage to my gun, as the S&W Mod 19 is not the strongest 357 on the market.

I may switch to 2400 for this application, as it seems to be a bit more accurate.

[runfiverun]

it also has a broader range of applications.
a powder that has a very narrow window HAS to stay in that window.
with the 2400 you can go down as alow as 7 grs and come back up to airc the 12-13 range.
almost doubling the powder/gas volumn, thats a good fit.
h-110 is for when you want to step up to the plate [so to say] and swing for the fence,it does THAT just fine [till it gets cold]

[shotstring]

When working up a load I prefer to use a heavy framed revolver. By doing so, I found I could afford to be a bit less patient in powder increments without experiencing signs of excessively high pressure. Once I got a load performing well, both in accuracy and pressure wise, I would feel pretty confident in moving it over to a lighter frame revolver.

It would probably be safer to back off on the powder just a bit when transferring over to a lighter frame, but to be honest, in all my years of loading I can't remember ever having a load showing excessive pressure to the degree that it risked damage to the gun and shooter without experiencing some signs of excessive pressure while working that load up in the heavier framed gun.

Of course, if you only have one medium or light framed gun, then there is no really safe alternative to just being patient and working up the load slowly and checking for pressure signs.

296 is my preferred powder for both 357 and 44 mag loadings.

[PacMan]

When i am looking for max. loads i start at the bottom working my way up one load at a time untill i find max.,for me and gun, and then start working back down looking for accuracy. Saves a lot of lead , powder and time./shot load one shoot and then move up a notch until max is reached.

[cbrick]

My question is: Can I substitute a cast boolit for a jacketed bullet without raising pressure?

Yes, I do it routinely. You are correct that cast will generate somewhat less pressure by virtue of both engraving and going down the bore with less resistance thus less pressure is generated and possibly a bit more velocity.

I can't speak to the max pressure for your Smith, my only Smith is a 624 44 Spec that I pretty much only shoot mouse fart, soda can murdering loads from. For my 357 I shoot a much heavier bullet (188 gr) faster than the numbers you quoted from a FA 357 using H-110 (same as 296). The difference between an FA and a Smith and safe pressure is huge so I won't post the load here. Do not load reduced loads with 296/H-110, these powders are for top end loads only. I suggest using 2400 as already mentioned for any load reduction you try.

Rick

[SlowSmokeN]

Are you able to call the powder manufacture or check their website for loading data?

[MtGun44]

Cast is softer and slicker (lower friction against the barrel) than jacketed. Pressures should
always be lower than similar jacketed. The few sources that show both types side by side,
verify this.

Bill

[ku4hx]

In the past I worked up "full" charges of both W296 and H110 for my Lyman 358156 SWC/GC. Gun was a 6" barrel Ruger Blackhawk. They all worked fine, but without a really hard roll crimp, and sometimes with one, I got a pretty wide range between highest and lowest velocity. Seemed to me the admonition for full power charges only and hard crimp were true. I got vastly improved spread figures with jacketed bullets.

After these results, I stuck with Bluedot and 2400 for full house cast loads. MV was a tad lower, 25-50 fps, but the spread between max and min MV was reduced enough for me to abandon the ball powders for cast boolits. Of course as is always the case YMMV.

[cbrick]

In the past I worked up "full" charges of both W296 and H110 for my Lyman 358156 SWC/GC. Gun was a 6" barrel Ruger Blackhawk. They all worked fine, but without a really hard roll crimp, and sometimes with one, I got a pretty wide range between highest and lowest velocity. Seemed to me the admonition for full power charges only and hard crimp were true. I got vastly improved spread figures with jacketed bullets.

After these results, I stuck with Bluedot and 2400 for full house cast loads. MV was a tad lower, 25-50 fps, but the spread between max and min MV was reduced enough for me to abandon the ball powders for cast boolits. Of course as is always the case YMMV.

Really, here are the chrono test results from 5 ten shot tests each testing the crimp in 357 mag, all used the same charge of H-110, CCI 550 primers and the RCBS 180 Silhouette @ 188 gr.

H-110 is an excellent full power powder; it burns clean and very uniformly when used with full loads AND preferably with heavier bullets.

1>
My normal profile crimp, second firing of WW brass, Carbide die sized
E.S. 30
A.V. 1518
S.D. 9

2>
Roll crimp, second firing of WW brass, Carbide die sized
E.S. 30
A.V. 1520
S.D. 9

3>
No crimp, second firing of WW brass, Carbide die sized, very slight bell
E.S. 30
A.V. 1528
S.D. 9

4>
Light profile crimp, virgin WW brass, not sized, not expanded, slight bell only
E.S. 26
A.V. 1532
S.D. 8

5>
My normal profile crimp, virgin WW brass, not sized, not expanded, slight bell only
E.S. 26
A.V. 1536
S.D. 8

Rick

[ku4hx]

Really, here are the chrono test results from 5 ten shot tests each testing the crimp in 357 mag, all used the same charge of H-110, CCI 550 primers and the RCBS 180 Silhouette @ 188 gr.

H-110 is an excellent full power powder; it burns clean and very uniformly when used with full loads AND preferably with heavier bullets.

1>
My normal profile crimp, second firing of WW brass, Carbide die sized
E.S. 30
A.V. 1518
S.D. 9

2>
Roll crimp, second firing of WW brass, Carbide die sized
E.S. 30
A.V. 1520
S.D. 9

3>
No crimp, second firing of WW brass, Carbide die sized, very slight bell
E.S. 30
A.V. 1528
S.D. 9

4>
Light profile crimp, virgin WW brass, not sized, not expanded, slight bell only
E.S. 26
A.V. 1532
S.D. 8

5>
My normal profile crimp, virgin WW brass, not sized, not expanded, slight bell only
E.S. 26
A.V. 1536
S.D. 8

Rick

Yep ... really. For me of course.

[excess650]

You've been given good advice, and already know that the M19 wasn't made for a steady diet of magnum loads. H110/WW296 is for magnum loads only in the .357 as the loading density needs to be high.

I shoot a 4" M19 and rarely feed it magnums. Mine gets slightly heavier than +P 38 loads with heavier boolits for normal "work". 2400 is a better fit for lighter than max loads and doesn't need a magnum primer.

[RevGeo]

You've been given good advice, and already know that the M19 wasn't made for a steady diet of magnum loads. H110/WW296 is for magnum loads only in the .357 as the loading density needs to be high.

I shoot a 4" M19 and rarely feed it magnums. Mine gets slightly heavier than +P 38 loads with heavier boolits for normal "work". 2400 is a better fit for lighter than max loads and doesn't need a magnum primer.

Excess, do you load 2400 in 38 Spec cases or 357 Mag cases or both for your 38+p loads? I've gotten mixed reactions from some folks about 2400 in 38 Spec cases with cast bullets, but Ol' Elmer did it quite a bit. Opinion(s)?
BTW I'm loading for a 6" Mod 19.

George