WW296 and .357 magnum in 686 and Marlin 1894C...

[Stargazer]

I have been trying to locate a powder and load that will give me better results than I have gotten using WW296. In the 4" S&W I was getting an average of 1120 FPS with a 15.5 grain load of WW296 pushing a 158 grain JSP bullet. The same round in the Marlin gave me an average of 1650! I feel I am wasting powder in the S&W to get magnum velocities out of that 158 grain bullet.

Any suggestions as to which powder may perform a little better by giving me some good magnum velocities from the revolver without wasting so much powder? I'd like to get around 1250 out of the 4" revolver with a 158 grain bullet and not use 15-16 grains of powder to do it with, yet still be safe. I am sure the rifle will perk up any load but to have a (500) FPS increase tells me the powder is being wasted in the revolver. Is my logic sound here?

Anyone have any experince loading for these two fine firearms?

[firechicken]

I only have limited experience with the 357 mag. I have a 4" GP100 and have tried 2400 and 296 for my 158gr loads. 15.0gr 2400 and 16.7gr 296 both got me right at 1200fps. The 296 give me a huge fireball and quite a bit of muzzle blast. Impressive to shoot, but I also have that "wasting powder" feeling. The 2400 loads have no noticable muzzle flash, but the primers are flatter than my 296 loads. Winchester lists 16.7gr as the max load for 296, and not to reduce it by more than 3% (16.2gr) to prevent squibs.

[Dogjaw]

Winchester lists 16.7gr as the max load for 296, and not to reduce it by more than 3% (16.2gr) to prevent squibs.

I was thinking the same thing before I read this. Be very cautious in reducing powder in magnum loads. There isn't much room to play. I have yet to load W296 below 16.5 gr in .357 mag.
As far as speed goes, the logic is right in that a longer barrel allows bullet speed to increase with slower powders pushing longer before exiting. You could try a faster burning powder, but quite frankly, that's why people buy longer barrels. Your only going to get so much out of it. For what it's worth, Speer lists 300 fps difference between a Marlin 1894 with 20" barrel and Ruger Security Six with 6" barrel with the same load.

[snuffy]

Stargazer, take a look at Alliant blu-dot. It's faster than either W 296 OR 2400. It should give you a bit more velocity in a shorter BBL. It's been a while since I worked up any loads for .357 revolvers, so I can't give any dirrect loads.

Unique might work as well, but you would probably run into pressure limits before you got top velocity. Also it would be quite colorfull with flash and blast in shorter BBLS.

[hoghunting]

I use H110, but it is almost identical to W296 - they are right beside each other on a burn chart. I've been very happy with the H110, but I also stay between the MAX and 3% below MAX.

[44 AMP]

It is what you expect from a 4" revolver. And the differences between loading manuals and individual shooter's guns.

No powder will get you real magnum performance from a 4" barrel without the "feeling you are wasting powder". There is no free lunch. If you want hisg speed, you have to burn powder, and the ones that produce the highest velocities when they reach max pressure are the "slower" ones. By burning slower, they burn further down the barrel, but when you go to a short barrel, those powders tend to burn alot past the end of your barrel.

I checked a couple of my manuals, and they maxed out about 1250fps with the 158gr JSP, from a 6" barrel!

The manuals give a pretty accurate "ballpark" figure, but individual guns can be faster or slower than the test gun used in the manual. Usually the variation is not much, but sometimes it is considerable.

Many years ago I was involved with testing some very hot 125gr .357 ammo. The guns were a 6" Model 19, a 6" Model 28, a Desert Eagle (6"), and a Marlin carbine (18.5"). The ammo clocked 1620fps from the Model 19 and was too hot for the gun. The Model 28 turned in 1670fps, and extraction was a little sticky. The Desert Eagle clocked 1720fps, and functioned fine. And out of the Marlin carbine, clocked 2200fps! So, a 100fps difference between the 3 handguns, all using the same batch of ammo. (Note, this ammo was way beyond what would be considered safe today, and infact was not safe in all the guns we tested. I mention is it because it was one of the largest differences between 6" guns I could remember seeing.)

Hercules (now Alliant) 2400 is the historical powder for the .357 mag. But, it is not at it's best from short barrels. Blue Dot is a little faster, and should perform as well in a shorter barrel. WW296 is very load density (and crimp) sensative, I don't use it in the .357, but I do use in the .44 Mag.
Unique will give you pretty good results, but will not reach quite the same velocity as 2400 before reaching max allowable pressure.

The oringinal (1935) load was a 158SWC at 1550fps from an 8 3/8" barrel, and was intended only for the ".357 Magnum" revolver. And would be considered unsafe in most of the .357 magnum guns on the market today.

[P-990]

Honestly, I agree that the "problem" is what you expect from a 4" revolver in terms of speed. I'd feel pretty good getting 1200 fps with a 158, and a little less would seem OK by me.

Try chrono-ing some factory ammo to see the difference. My magnum revolver experience centers around the .44 Magnum, so the results will vary, but it will give you a good idea. I've always thought that Winchester's 240gr JSP stuff, in the white box, felt kind of "hot" from my poor Smith and Wesson. Over the chronograph I got 1400-fps!! Granted, that's a 6" barrel, but that's smoking. I aim for about 1200-1300 with my reloads in the same bullet weight.

Out of my 20" Marlin rifle, those loads would clock 1750-1800 fps with ease. Again, my reloads run about 100-fps under that.

All I can suggest is bumping your 296 loads up, but don't go past the book. Unfortunately all you're going to get is all you're going to get.

[flintsghost]

I like 2400 with a CCI magnum primer with a 158 grain jacketed hollow point.