I was looking in my lyman manual and noticed even the +p loads that are listed for the 38 special are still less than half the pressure that the 357 mag is loaded to, my question is why can't the 38 special be loaded to the same pressures as the 357 mag provided the gun is modern

Well, there might be several reasons.

First is that even in the same or related model firearm, guns of different calibers are not built to handle the same pressures. The old K-frams Smiths are an example, where the .357s were made of different steels or heat-treated differently than the .38s.

The other danger in that ammo so loaded can be put into a "weak sister" type firearm and fired, possible destroying the gun and injuring the shooter.

I have many revolvers in .45 Colt. I load some loads very heavy for the Rugers and some are loaded with normal loads for the Colts and Colt clones. However, in order to practice this madness, I have a rule: Any .45 Colt cartridge loaded with a jacketed bullet is only fit for a Ruger or Contender. Any .45 Colt cartridge loaded with a lead bullet is safe to fire in any revolver.

Clearly something is needed to keep things straight.

Well, three things come to mind. First, the case volume is much greater in the .357 as compared to the 38 special. Greater case volume reduces pressure to a point. Second, the amount of steel between chambers is greater in the .357, and composition of the steel that makes up the cylinder is of a higher tensile strength.

I went to high school with a kid that modified a 38 to accept .357 ammo with a twist drill. The bullets had to be deep seated to clear the end of the cylinder. He tied it to a tree and used a string to pull the trigger. His $100.00 S&W K-38 cylinder broke in 3 large pieces, and many small ones. A K-38 is a heavy frame pistol in the 38 special class.

quote:

Originally posted by cummins cowboy:
I was looking in my lyman manual and noticed even the +p loads that are listed for the 38 special are still less than half the pressure that the 357 mag is loaded to, my question is why can't the 38 special be loaded to the same pressures as the 357 mag provided the gun is modern

It's possible, but not recommended. The 357 came to be when police were looking for more power to penetrate automobile bodies. Credited with much of the final developmental work were Maj. Douglas B. Wesson and Philip Sharpe. By stretching the 38 Special case .100" they created the 357, and by increasing pressures, they doubled velocity and tripled energy levels. Besting the 30 Mauser, the 357 Magnum remained king of handguns until the advent of the .44 Magnum in 1955.

All good points. As far as K-Frame Smiths, the heat treating process is considerably different for a model 10/15 and a model 13/19 where the .357s get a significantly higher tensile strength of the steel. Even then, there is considerable difference among .357 magnum revolvers themselves. One reason SAAMI lowered the MAP, maximum average pressure to 35,000 PSI for factory ammo was because of the model 19 whereas heavier revolvers like the L-Frame and Ruger GP-100 were built to deal with original pressure spec ammo.

Before there was a .357magnum, trepid handloaders pushed the .38sp case to magnum limits in large frame revolvers. I don't see why you couldn't do that today & use them in a .357mag. but why?

i wonder if the brass is a different thickness between the 38 and 357,in the areas of the head and rim?? Could there be a difference in 38 and 38+P brass??? I seem to remember reading that Starline brass in 45acp and 45acp+P were different, the +P being thicker.

quote:

Originally posted by 243winxb:
i wonder if the brass is a different thickness between the 38 and 357,in the areas of the head and rim?? Could there be a difference in 38 and 38+P brass??? I seem to remember reading that Starline brass in 45acp and 45acp+P were different, the +P being thicker.

one could always trim 357 mag brass down. I just don't see why the 38special can't be loaded to the same pressures as long as the firearm is heavy duty enought to take it

CC: there is a good reason to consider it, depending on your views on using handloads for defense. With S&W revolvers with barrels under 3" you get a short ejector rod. This has proven to be detrimental at times when a fast reload is required. Another case: seven shot revolvers. I have experienced sticky extraction with a few; going to .38 Special length cases improves things dramatically. Some people will tell you that .38 Special +P cases are the same as .357 Magnum brass, except in length. I trim .357 Magnum cases to .38 Special length for the warmer loads. One reason that I do this is so that .357 Short Magnum loads will have a .357 Magnum headstamp. Comparing trimmed .357 Magnum cases to .38 Special +P, you will find little or no difference in wall thickness. I have done a good deal of load development and there are a couple of powders that really excel for this: AA#7 and V-V 3N37. Others can be used, but things like load density and flash come into play. Both 125 and 140 gr. JHPs can be used. I've never been interested in using 158s or 180s because I prefer the lighter weights for defense loads. The longer bullets may cause some case bulging as well, depending on the brass. I believe I have used some 158s in the past, I'd have to check to be sure. I've also used some Rem. 9mm 124 gr. JHPs in the Short Magnum cases simply because I had so many of them at times. A Taper Crimp will be required.

With revolvers that will chamber them, .38 SUPER +P ammo can be fired in a .357 Magnum revolver because of the semi-rim on .38 Super cases. The Super is a 36,500 PSI round and considerably shorter than the .38 Special case. Working loads up carefully and watching for pressure signs along the way, there is little reason why you can't load the shorter cases to match full length factory loads that are usually around 35,000 PSI. Flash and muzzleblast can be reduced significantly. You wont have the unused case capacity that you would in using slightly faster than true magnum powders in a full length .357 Magnum case. AA#7 can actually push velocity as high as many magnum powders in full length cases, and Blue Dot will exceed many of them, but Blue Dot will flash brightly in .357 Magnum or the Short Magnum. Slightly faster than magnum powders like AA#7 and 3N37 have another benefit: The losses in velocity will not be as high as they are when you fire rounds loaded with magnum powders if you compare them with say 6" revolvers, then in a 2.5 or 3" barrel. AA#7 can be outstanding in accuracy in full length cases loaded at "medium velocity", or slightly less than full magnums. It works very well in the Short Magnums for all of the reasons you would associate with a good defense load. Data is going to be a problem, but in the absence of anything else, you can use .38 Special +P charges for start loads in the .357 Short Magnum case. If you use AA#7 or V-V 3N37, I can help with a start charge if you send a PM.