.38/.357 ammo question

K

kymasabe

New member
I recently posted a question about the Nagant revolver and the ammo size and different ammos that can be used in it and it got me thinking about .38 and .357.

The question is...how CAN you use .38 in a .357? Theoretically, 357/1000's of an inch is smaller than 380/1000ths. Is the .38 and .357 the measurement of the diameter of the bullet or of the case? If it's the case...does it fit snugly where a .357 fits well. Or, if it's bullet diameter, does the .38 get compressed down the barrel? Sorry folks but I never really understood how that worked.
 
The bullet diameters are for all pratical purposes the same. Same for the cases. The main difference in 38 and 357 is case length & pressure. Forgot about diameter in this discussion.
 
Good question. There is actually no such thing in modern times as a .38 caliber revolver, at least that I've ever heard of. They are actually .35 caliber handguns.
Bore (land) diameter of .38s is nominally .349. Grooves are cut .004 deep, yielding a groove diameter of .357.
Jacketed bullets are usually .357, same as groove dia., and lead bullets .358.
So, .38 and .357 are the same caliber, but different cartridges.
.357 is thus the diameter of the bullet and groove, whilst .38 is something dating back to the Civil War.
JT
 
Yep, that is true of many calibers - the number is just a name, and is *similar* to the true size, but it is not the true size. Can find out the true dimensions in a site like ammoguide.com.
 
CarbineCaleb said: the number is just a name, and is *similar* to the true size, but it is not the true size.

Very well said.
 
I think the .38 designation comes from the time when the predecessor cartridges to the .38 Special (e.g., .38 Short Colt) used outside-lubricated bullets which fit into the cartridge case like a .22 rimfire does today.
 
Also note that 9mm is pretty much the same size as the other 2. Dont try it unless your gun is built for it though. Taurus makes a few revolvers in their Triad Series. Model: TRIAD-85B
Caliber: 9mm/.38/.357

The Taurus Triad shoots 9mm, .38 special and super, and .357 Magnum out of the same gun. Use the five stellar clips included for the 9mm and just load up with the other when you want to and it shoots them all. This is a one-gun solution to the extra ammo you have in the shed. The small frame model holds five round of your favorite person protection round and the Tracker holds seven.
Click to expand...

 
My understand is the 38 was originally really a true .38 cal bullet that was the same diameter as the case it was fired from (black powder at the time.) It's base is "dove tailed" into the case.

When the modern version of the cart. was created it fit the bullet into the case without a grove that forced seating to a particular orientation. The marketing department thought they would keep the 38 designation in an attempt to garner military buying (bigger is better idea).

357 just lengthened the case and increased cup pressures.
 
Good point. The whole matter may go back further in time to the M1851 Colt Navy cap and ball cal. .36 revolver. Bore diameter was .36. The grooves (I think) were cut .006 deep, so the groove diameter was about .372.
The lead balls were about .375, which rounds off, of course, to .38.
I don't know when the number .38 appeared, but I suspect it happened when converters bored the cylinders through to accept the new self-contained metallic rimfire cartridges, and someone decided to name the things after the bullet diameter rather than bore diameter.
IN the 1870s, both S&W and Colt introduced center fire handgun cartridges, and both decreased bore diameter from .36 to .35, but retained the number .38. This was likely done, as fisherman suggests, for marketing reasons.
JT
 
You must log in or register to reply here.
Back
Top