Bothersome question on .38

[mag627]

At least it bothers me.
I understand that 9mm ammo is .355
I understand that .357 ammo is .357
but if it uses the same barrel/cylinder/casing dia. etc.

why is it .38? not say .36?

if you know, please let me know.
Cheers

 

[slicknick]

why is it .38? not say .36?
Cheers

I have heard two reasons why:
1) That originally, .38 cartridges (.38 Long Colt, .38 S&W, etc) were lubed outside of the bullet as they did not have grooves in the bullets themselves, which demanded a smaller bullet with the lube adding to the overall outside diameter (.357 bullet plus .23 of lube = .38)
or
2) They measured from groove to groove instead of land to land, much like why the .303 British is actually .311-.312 in diameter

 

[Hi-Standard]

I have heard two reasons why:
1) That originally, .38 cartridges (.38 Long Colt, .38 S&W, etc) were lubed outside of the bullet as they did not have grooves in the bullets themselves, which demanded a smaller bullet with the lube adding to the overall outside diameter (.357 bullet plus .23 of lube = .38)
or
2) They measured from groove to groove instead of land to land, much like why the .303 British is actually .311-.312 in diameter

The 38 Special may have been a heeled bullet like the 44 American. When the 44 was first developed the bullet diameter was the same size as the cartridge, much like the 22 Short, Long, and Long Rifle rounds are today. The bullet had a smaller diameter heel which fits inside the cartridge. 44 bullets were first reduced in size by the Russians I believe for the 44 Russian. 44 Special and 44 Magnum bullets are now only .429" in diameter.

 

[green]

Original 38 Long Colt had a heel type bullet .375" dia.
Real reason that it is called a 38 is because that is what the manufacturers called it.

 

[curtmg]

that is what the manufacturers called it.

Sounds like how most cartridges get their names