38 Special +P using 357 cases.

walnutred

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Recently I picked up a revolver whose barrel is marked 38 Special but the cylinder is bored for 357 Mag, a round for which this revolver was also manufactured. Out of curiosity I would like to load some 158 gn ammo to 38 Special +p specs using 357 brass and load some using 38 Special brass. I'd like to see if there is any noticeable accuracy difference using the longer cases. Before I try and reinvent the wheel has anyone here done this?
 
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I load hot 38 special into mid 357 mag using Longshot. I haven't noticed any accuracy difference using one case or the other.

If you want try a bulky powder like trail boss. I seem to remember 5 grains of trail boss and a 125 gr plated bullet gave me great accuracy in a 38 special case going 900fps. You could build up a little from that in a 357 case and still have a pretty light load.
 
I've loaded a bunch of +P 38 loads in 357 cases using ~ 4.4gr AA#2 and 158gr lead or plated bullets. Works great - no issues at all.
 
If you shoot well enough to tell the difference between 1" groups and !.5" groups at 25 yds, it might matter. I have a reflex sight on a 4" 66 and I've done just that shooting from the bench. Therefore, I use .357 brass for my steel challenge loads in that gun ... which I use to shoot 12" plates. That degree of accuracy is totally unnecessary, of course, but I like knowing I have it. In competition, confidence is paramount.

The point is, you might be able to distinguish an accuracy difference, but I doubt it's going to be like night and day. Whether it matters or not is dependent on what you intend to shoot at.
 
If you are sure,absolutely sure that the gun was manufactured to handle .357Mag pressure,I'd go with a medium burning rate powder(like Unique,800X and a few others)and start with nothing heavier than a .357 starting load.
But I'd first make sure that the gun has the .357Mag heat treatment;not just the markings.It is easy to rebore a .38spl cylinder to .357 specs and from your description your gun sounds like it's been tampered with.
Just out of curiosity,what brand and what frame size is it?
 
What you propose is fine.....

No problem with shooting .38 +P out of .357 cases in the .38 special case. My question is 'how did the gun get bored for .357??? Or was it mismarked. What is the model number?

I do it all the time. Most of the .38 cartridges that I reload for my 686 are in .357 cases. The only problem with shooting .38 from a .357 chamber is the crud ring that keeps .357 cartridges from seating good that has to be cleaned out. I never liked starting with .38 at the range then trying to load .357. It'll brush right out, but to me it's a distraction.
 
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What make and model of revolver is this?

Would like to know also, I am guessing it is a ruger sec six, or GP100. They are police/security models that are stamped, and chambered 38 spl. But they are exactly the same as the 357 models, including heat treating. There have been some that have had them cut for 357. I have not bothered with my GP100, I just use 38-44 loads in it.
 
This is an European police surplus Astra 960 which were built on the heavier 357/44 mag frames rather than the smaller frames they normally used for 38 Special revolvers. Since this was a limited run I suspect they simply roll marked the barrels to meet the 38 Special requirements of the contract rather than create a new manufacturing process. I don't plan on running 357 mag through it but I was wondering if there is any advantage to using 357 brass as I have a few hundred available.
 
The magnum brass is longer and has greater internal capacity, thus pressures generated by any given load can be expected to be lower than the same load in a shorter .38 Special case. As with any reloading operation, the only safe course of action is to work up your loads for the brass, bullets, primers, powders, and gun they will be used in.
 
I load a 158 grain 38 Special +P load into .357 cases using a 105 gn LRNFP projectile to ensure reliable feeding through my Henry Big Bore .357 rifle.

I test fired a few in my 686-4 and found that the recoil, as expected with the lighter bullet, was much reduced. The muzzle flash also seemed significantly less than from the .38 +P loads, probably a result of lower pressure in the longer cases. I didn't bother testing accuracy in the revolver but from the rifle they shoot tighter groups than standard pressure .38 loads and feed much more reliably.
 
5.5 gr. Unique, 357 brass, standard primer, 150 gr. Speer Cast SWC, 4" barrel, 860 chronoed fps, A little hotter than +P, I have been told. Nice to shoot! Should do about as good with 158 gr. cast bullets.
 
Thanks, I'll try the Unique load first as I have plenty on hand. I've never tried a scope on a handgun but if the group reduction ratio you mention is consistent it's worth trying the 357 brass. 25 yards off hand with iron sights I have no hope of telling the difference between a 1" load or a 1.5" load, but I can tell the difference between a 4" load and a 6" load.
 
Telling the difference between 4" and 6" is a good point.

I start my load development at 50 feet from sandbags because it's easy to spot losers and It's satisfying to see tiny groups. If it won't shoot well at 50 ft, I'm not interested. Then I take the top 2 or 3 loads to 25yds. A 1" group is plain good. But it can be tough to be certain a 1.5" group is all that worse. Finally, at 50 yards, it's not very exciting looking at 3" + groups but it's usually pretty easy to pick a winner.
 
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