38 Special loads in .357 case

[ARK]

I am new to revolver reloading, trying to develop light steel challenge load for my Ruger GP100 .357 Magnum using powders I have on hand from shortage times when we were getting what we could not what we wanted. The question I have for experienced Revolveros  out there is:

When you load 38 Special loads into .357 case, can you seat bullet to 38 Special seating depth?

[TrackCage]

2 hours ago, ARK said:

I am new to revolver reloading, trying to develop light steel challenge load for my Ruger GP100 .357 Magnum using powders I have on hand from shortage times when we were getting what we could not what we wanted. The question I have for experienced Revolveros  out there is:

When you load 38 Special loads into .357 case, can you seat bullet to 38 Special seating depth?

I wouldn't do that.

 

What you're asking though - about a reduced power load in magnum brass - is something I do frequently in 44 Mag. In fact, I don't own or load any 44 special brass. I use upper-end 44 special load data and forget about it.

 

My reasoning is simple. in 44, magnum brass is FAR more common than special brass. I wouldn't do this in 38/357 because 38 special brass is so common. 

[Guy Neill]

In the most technical sense, you could likely do that.  You most likely do not want to however.

 

There would be a gap between the case mouth and the bullet making loading the cartridges into the chambers more difficult.  You also will not be able top crimp the bullet, though youo could crimp the case.  The bullet running into the crimped case mouth will not likely enhance accuracy.

 

Best top seat the bullets with relation to the crimping groove and case mouth.  So, longer OAL for the 357 Magnum cases,.

 

If you do not have a chronograph, you may want to consider one.  Working up loads is better done with one.  The longer 357 Magnum cases will give some amount lower pressure with a given load than the same load in a 38 Special case.  The chronograph will allow adjusting the load to match the 38 Special velocity.  Accuracy is still to be found by working through the load range.

[K-Texas]

2 hours ago, ARK said:

I am new to revolver reloading, trying to develop light steel challenge load for my Ruger GP100 .357 Magnum using powders I have on hand from shortage times when we were getting what we could not what we wanted. The question I have for experienced Revolveros  out there is:

When you load 38 Special loads into .357 case, can you seat bullet to 38 Special seating depth?

 

Yeah, they'll need to be in .38 Special cases. Except if you have wadcutters. Then loads only need to be a tad longer than the .357 Mag. case. In some cases, flush.

 

What it really comes down to is what powders do you have? Because light charges won't fill much of the case, you'll do best by using a powder that isn't sensitive to powder positioning. I don't recommend TiteGroup for high pressure cartridges like 9mm, but it will do well for Minor PF .38 Special loads. If you don't have it, there are plenty of other good choices.

Edited February 27, 2020 by K-Texas

[ARK]

Thank you for your responses. You all are raising important points. I am reloading for 6 pistol calibers and I have chronograph and I am using it working on my load development. I just don't have experience with revolver. I am trying to use what I have on hand instead of buying more powders.

I have on my shelf:

WST (one lbs left )

WSF

Accurate #7

Green Dot

3 N 37

N 340

N350

Autocomp

Bullets: lead 140 grain, plated 125 gr

Being used to SD of 12 for precision rifle I was taken back to see SD in the 50's for some of 357 Mag loads.

Also, started with SP Magnum primers and had about 10 % misfires and unburned powder in lighter loads.

I am used to lighter bullets for 38 SC and 9 Major but I see most of the people use heavier bullets in .357?

I would appreciate if you could share with me your bullet/powder/velocity combination. Not asking about specific powder load if you don't feel comfortable posting it.

 

[K-Texas]

16 hours ago, ARK said:

Thank you for your responses. You all are raising important points. I am reloading for 6 pistol calibers and I have chronograph and I am using it working on my load development. I just don't have experience with revolver. I am trying to use what I have on hand instead of buying more powders.

I have on my shelf:

WST (one lbs left )

WSF

Accurate #7

Green Dot

3 N 37

N 340

N350

Autocomp

Bullets: lead 140 grain, plated 125 gr

Being used to SD of 12 for precision rifle I was taken back to see SD in the 50's for some of 357 Mag loads.

Also, started with SP Magnum primers and had about 10 % misfires and unburned powder in lighter loads.

I am used to lighter bullets for 38 SC and 9 Major but I see most of the people use heavier bullets in .357?

I would appreciate if you could share with me your bullet/powder/velocity combination. Not asking about specific powder load if you don't feel comfortable posting it.

 

 

That's pretty good coverage in terms of the powders. Most wadcutters are around 148 grs. so that wouldn't be a great increase. There are a few cast/poly-coated makers that offer 141 gr. Wadcutters. In terms of cast and poly-coated bullets I like 158 gr. SWCs for .357 Mag. and JHP loads get large charges of powders that are slower than what's on your list, but AA No 7, 3N37 and N350 can get velocity equal to factory loads. The problems you are seeing with large SDs is pretty much about the unused space in the case, where a .38 Special case would improve that. Wadcutters would help cut down on that unused space since they seat much deeper than what you're using. But for Minor PF loads, I think you'll find it in your advantage to get some .38 Sp cases. Then try Green Dot and WST in the .38 loads, maybe WSF.

 

I also shoot a 4.2" GP100.

 

 

Edited February 28, 2020 by K-Texas

[Postal Bob]

I also have a GP100, but I use 38 special cases, simple because they're so plentiful. As a reference, my loads are 3.2 gr Titegroup, over a 158 gr coated lead bullet. Power factor is around 105 pf. I use them for IDPA matches. Titegroup works great, when small quanties of powder are used in a large capacity case like the 38 special.

The bigger advantage to using the 38 special case vs 357 mag, is the shorter case length. This makes for easier reloads on the fly. Have you tried inserting a speedloader full of 357 mag into the GP100? Or quickly ejecting a cylinder full of empty 357's? t's not so easy because of the length, especially if you use larger rubber grips like I do. That is also the reason why people load 38 short cases to use in 38 special revolvers for action pistol matches. Much faster and easier reloading on the fly.

 

Btw, get yourself the Wolff spring kit for the GP100. It'll lighten the trigger pull to somewhere near 5lbs double action. I use the lightest main spring and trigger return spring in mine. I have no problem setting off Winchester primers. With magnum primers, I'll get a misfire every once in a while, especially in colder weather.

[ARK]

Wolf sprigs on the way. Next testing batch is going into 38 Special case. I started with 357 case because of infamous crud ring. Learned since that this is not a real issue. 

[perttime]

Loading .357 a bit short might depend on the bullet. I've been loading some plated 158 grain Truncated Cone bullets so that I crimp right where the bullet starts to taper. Seems to work OK.

My loads, so far, have been with 3N37 and N340, and pressures are evidently on the low side approaching IPSC Major PF. A faster powder would be needed for "light" loads.

[Postal Bob]

On 2/28/2020 at 10:12 PM, ARK said:

I started with 357 case because of infamous crud ring. Learned since that this is not a real issue. 

Only a real problem if you shoot hundreds of 38, then try shooting 357. Even then, not much. 

But what I do after shooting much 38's, is take a .40 cal bronze brush, attach it to a portable drill, and spin it in the front end of each cylinder. Cleans out any crud line that may be there.