How to make a .38spl level load in a .357mag case?

[chaim]

This may be a stupid question but you know what they say...

One of my reasons for picking .357mag to start reloading is that like many I often shoot .38spl out of my magnums but I am sick of the lead ring that results. However, since I have a nice K-frame S&W 65LS and I'm getting a beautiful (nearly unfired) P&R S&W 19 I don't want to shoot only magnum powered loads because I want to get the maximum life out of my K-frames (of course the L-frame I'm not too worried about).

The Lyman reloading manual I have strongly advises against going below minimum loadings. However most of the starting loadings for .357mag seem to be truely magnum loadings (they have significantly higher pressure levels than even the max load .38spl loadings).

I recognize that I can't simply put a .38spl load into a .357mag case and expect the listed performance of the .38spl load because the extra case length will effect pressure levels and performance. What is the safest way to address this? Should I back down the published .357mag loads a specific percentage (for example, lets say 10% less powder than the starting load)? Should I use the max .38spl listing? Then again, I think I read somewhere that leaving more space in the case (as either of the above options would) can actually increase pressure levels. Are there manuals that will actually publish load data for someone looking for .38spl performance out of a .357mag case?

If I stick with the starting loads (more mild .357mags) and look for those w/ lower published pressure levels is this even something to worry about? If I use .357mag loads but the lower pressure/more mild loadings only, should my K-frames be fine? I mean they are .357mags, are these lower level starting loads essentially ideal for a K-frame magnum?

I can't be the only person out there who wants to do this. I'm sure there are people who want to make essentially .38spls for their K-frame .357mags but without the extra cleaning of using the shorter case in the chamber.

 

[David Wile]

Hey Chaim,

Your 357 is designed to shoot 357 Mag, 38 special, and all the +P loads inbetween. Since you can obviously shoot the much lower 38 special loads safely in your 357 Mag, you can simply use the 38 special load data in your 357 Mag cases with no problems. Many folks load below posted data, and there really is no problem as long as the load is stout enough to push the bullet out of the barrel. Loading that low is really an exaggeration, but reducing pistol loads by 25% is no real problem - especially with the regular "pistol" type powders.

Obviously, you cannot use 357 load data in 38 special cases since they could be fired in a 38 special pistol, and that would be a bad thing to do. I hope I have understood your question and answered it properly for you.

Best wishes,
Dave Wile

 

[Cal4D4]

My view is go to the sites of Alliant Powder, Accurate Arms and Hodgdons, just to get started. Look at the wide range of power levels powders such as Blue Dot, Power Pistol, AA#5 and AA#7 and HS6 are used in. In the manner you are doing this, I have varied these powders from suggested .38 Special levels to suggested max .357 loads and I feel you could dial in the desired power in that range. Very easy to get good results. Some loads will burn cleaner than others. Some loads can be hard to see down in that long skinny case.

 

[stans]

I reload a lot of 357 Magnum cases and I found that I can pretty closely duplicate a 38 Special load by adding 0.5 grains to the listed 38 Special load. This generally gets me very close to 38 ballistics in the Magnum case. I use standard primers with these loads. The only time I would use a magnum primer would be with W-296 and H-110, which you do not want to reduce more than 10% from maximum charge, or possibly AA#9.

Using reduced power loads in your K-frame Smiths may result in the gun out living you!

 

[Desert Dog]

For .357 magnum cases, I love 10.0 grains of AA#7 under a 125 grain lead FP for target loadings. Super accurate in my SP101, and very low recoil.

Mike

 

[braindead0]

4.5 grains bullseye behind 158gr LRN here, last time I chrono'd this it was about 925fps.

 

[moxie]

You will still get that ring, even when using magnum cases. It will be about .035" farther down the bore. I just use a good chamber brush, sized a little fatter than a bore brush, and have at it.

 

[moxie]

Make that .135".

 

[MoNsTeR]

Well, the best way to hit your performance target is to use a chrono, but that may be infeasible. If you're just putting holes in paper, who cares about the velocity, just play around until you get the accuracy you want. If you're trying to duplicate some other load, play around until it "feels" right.

Using the listed max for .38 in a .357 case as a starting point should be perfectly safe.

 

[Standing Wolf]

I recognize that I can't simply put a .38spl load into a .357mag case and expect the listed performance of the .38spl load because the extra case length will effect pressure levels and performance.

I've been doing it for years. I make very light .38 special target loads in .357 magnum cases, and have never encountered a problem. The extra 0.10" case length may slightly reduce velocity, but has made no perceptible difference in accuracy. I use as little as 2.5 grains of Bullseye with a 148-grain hollow-based wadcutter and standard primers for my Colts, and as little as 2.7 grains of the same powder for Smith & Wessons.

 

[coonan357]

Chaim Buy more books !!! I have found several that list the starting points for the hottest .38 loads to be the begining of .357 loads , just beware when firing for the first time for the unussual noise of the stuck bullet syndrome (it happens )

 

[winwun]

Chaim, listen to Standingwolf. I too shoot reduced loads because of arthritis, but I demand accuracy. I shoot the 110 gr win HBHPMJ over 4 to 5 grains of Bullseye, and it works great in the .357 case. This, incidentally, is about a 33% reduction off of book. Don't be afraid to experiment, Roberts, O'Connor, Rigby, Whelan, and a whole bunch of other guys did, and look what happened. Just use some common sense, and also, full face shields and gloves aren't a bad idea until you are sure of the load. Another "odd" load I shoot in my Ruger BH .357/9mm, is a 9mm case with about 5 or 6 gr of Bullseye and the above .357 bullet. It is super accurate out of the BH, and with 4 gr of Bullseye works well in my 9mm autos and is more accurate than standard load 9mm stuff. The guys I shoot with tease me about the cartridge having a "panty line" because of the .002 oversize bullet in the 9mm case. Another thing, a light load in a .357 case will be more accurate out of a .357 pistol than the same load in a .38 spl case fired in the same .357 pistol. Enjoy trying new stuff -- that's what loading is all about.