38 special in a 357 mag revolver - how is this accurate?

[44Blam]

I know that it works and is accurate... But I got to thinking about it the other day and I thought that when you go to fire the boolit, it has to jump 0.15" to get to the cylinder throat before it goes another 0.25" or so to get to the barrel through a gap... Does it ever shear off some of the lead/coating when hitting the cylinder throat?

Anyway, the more I thought about it, the more I wondered how all this can happen without the boolit getting all off balance before being squeezed down the barrel. I also think about my most accurate and powerful pistols - they are revolvers.

Anyway, thought I would throw this out to see if anyone knows how all this happens and still maintains so much accuracy. Also, why isn't a whole ton of energy lost at the cylinder gap?

[bmortell]

just guessing maybe the velocity is so low at that point in time that it don't really take much damage easily

[tazman]

The boolit is still supported by the case walls as it enters the throat of the cylinder. The throat supports the boolit very tightly until the base of the boolit clears the cylinder, at which time the nose is already into the barrel and probably into the rifling.
A boolit would need to be very short or very small in diameter to get out of alignment during this process. All boolits, that I know of, are longer than .15. Most are long enough to make the jump from cylinder to barrel without tipping before contact. Most still have the base supported by the cylinder as the nose passes the forcing cone, thereby having both ends supported at the same time.
There is a significant amount of energy lost due to the cylinder gap. How much depends on how wide that gap is.
Even so, things are moving fast enough that the boolit is long gone before too much is lost through the gap.

[Outpost75]

The Keith type bullets with long nose and full-diameter front driving band when loaded in .38 Special brass, and fired in a .357 revolver, are well guided in their transition exiting the case and entering the cylinder throats and they shoot accurately. Accurate 36-175H is an example, 36-168H is another. Note that nose length is the same on the lighter bullet, and that the weight difference results in reduced seating depth, not overall cartridge length.

252371252418

Factory .38 Special +P and .357 Mag. Velocities and .38 Special (.38-44) Handloads

Ammunition____________________S&W .38-44 HD 4”____Colt New Service .357 Mag. 5”

Factory Loads for Reference:

.357 Mag. Super-X 158-gr.Lubaloy__1236, 8Sd (S&W Mod. 28)_____1307 fps, 36 Sd
.357 Mag. Rem-UMC 158-gr. SWC__1221 fps, 23Sd (S&W Mod28)__1287 fps, 27 Sd

Old Super-X 158-grain LRN .38-44___994 fps, 23 Sd____________1024 fps, 11 Sd
Winchester X38SPD 158-gr. LHP+P__909 fps, 16 Sd_____________936 fps, 16 Sd

“.38-44” Handloads in .38 Special brass, W-W cases, WSP primer:


Acc. 36-175H 4.0 grs. Bullseye+P_______871 fps, 5 Sd_____________902 fps, 14 Sd
Acc. 36-175H 5.5 grs. AutoComp+P_____902 fps, 14 Sd____________947 fps, 11 Sd
Acc. 36-175H 11.5 IMR4227+P_________914 fps, 22 Sd____________981 fps, 18 Sd

[curioushooter]

The boolit is fairly well supported as it closes the distance between the case mouth and enters the throat. You can get some lead shaving accumulation if you are in the habit of greatly oversizing the boolit. I size .357 or .358.
I had a .375 Winchester contender that I shot with cut-down brass to 1.8" to be legal in Indiana and it was just as accurate as using full length brass...I couldn't tell the difference at least.

[Petrol & Powder]

I know that it works and is accurate... But I got to thinking about it the other day and I thought that when you go to fire the boolit, it has to jump 0.15" to get to the cylinder throat before it goes another 0.25" or so to get to the barrel through a gap... Does it ever shear off some of the lead/coating when hitting the cylinder throat?

Anyway, the more I thought about it, the more I wondered how all this can happen without the boolit getting all off balance before being squeezed down the barrel. I also think about my most accurate and powerful pistols - they are revolvers.

Anyway, thought I would throw this out to see if anyone knows how all this happens and still maintains so much accuracy. Also, why isn't a whole ton of energy lost at the cylinder gap?

I think if you were to examine the drawings of the two chambers (38 Special & 357 mag) you would probably have one of those moments where the light bulb comes on and it becomes clear.

I don't have a real good way to show that here, so I'll try to explain it.

While it's true the 357 mag cartridge casing is 0.135" longer than a 38 Special casing and therefore the 357 mag chamber is longer by roughly the same amount, the bullet doesn't "jump" that distance. That isn't quite an accurate characterization.
The chamber transitions to the throat but that occurs over a distance much shorter than the length of the bearing surface of the bullet. As the bullet exits the casing and enters the throat, the bullet is still partially in the casing. It doesn't "jump" that transition between the end of the chamber and the throat.

It's also important to consider the shape of the chamber as is transitions into the throat. While it is fairly abrupt, it isn't a sharp 90 degree ledge.

The same thing occurs when the bullet leaves the barrel and enters the forcing cone. The base of the bullet is still in the cylinder throat as the forward section of the bullet enters the forcing cone/barrel.