Novice Question Here about Calibers.

[Blue Steel Traveller]

I've been trying to figure out the caliber numbering scheme and can't seem to get a clear defition of the calibers and what the numbers mean. So when talking about the Spencer 56/50 and the 44/40 what does the first number mean and what does the second number mean?

Thanks

 

[Major 2]

Caliber/grains of powder

32/20
38/40
44/40
45/70
45/90
45/110 .....

[Blue Steel Traveller]

Thanks - That makes a great deal of sense now

[Fox Creek Kid]

The 56 in 56-56 Spencer was the rudimentary diameter of the cartridge case in thousandths of an inch. The 56-50 was originally called the .50 Springfield Carbine. I won't confuse you more with groove diameters. 

[Drydock]

Most of the time when you see these designations they go -caliber-charge weight-bullet weight.  IE .44-40-200,  also know as the .44-40, or the .44 WCF (Winchester Center fire) This is a system established for BP centerfire calibers in the late 1860s.

HOWSUMEVER!  The rimfire Spencer calibers use a different system, mostly due to the fact that when these rounds were first created (Circa 1860-1865) there was NO system for cartridge nomenclature yet established.  When C.M. Spencer created his first round, it used a .56" diameter (more or less) heel type outside lubed bullet (Same as the current .22 LR) loaded in a .56" diameter case.  Thus he called it the .56/.56.

In 1865, Frankford Arsenal reduced the barrel diameter to allow a bullet to be loaded inside an enlongated version of the .56 case, thus creating the .56/.50. (Also known in goverment service both as the .50 Carbine, and as the .50 Spencer) C.M. Spencer for some reason did not like inside lubed bullets, and created an alternate round using a shorter .56 case with a slightly larger Heel type bullet, calling it the .56/.52.  This could be fired in the same chamber as the goverment .56/.50 round.  This latter round really succeeded only in confusing folks, as it does to this day.  The Goverment as well as private buyers perferred the inside lubed .56/.50.

Note there is no powder designation in any of these rounds.  The Spencer rimfires held around .45 grains.  In fact I don't know of any era rimfire rounds that used the standard nomenclature of the later CF rounds.   

[Major 2]

Most of the time when you see these designations they go -caliber-charge weight-bullet weight.  IE .44-40-200,  also know as the .44-40, or the .44 WCF (Winchester Center fire) This is a system established for BP centerfire calibers in the late 1860s.

HOWSUMEVER!  The rimfire Spencer calibers use a different system, mostly due to the fact that when these rounds were first created (Circa 1860-1865) there was NO system for cartridge nomenclature yet established.  When C.M. Spencer created his first round, it used a .56" diameter (more or less) heel type outside lubed bullet (Same as the current .22 LR) loaded in a .56" diameter case.  Thus he called it the .56/.56.

In 1865, Frankford Arsenal reduced the barrel diameter to allow a bullet to be loaded inside an enlongated version of the .56 case, thus creating the .56/.50. (Also known in goverment service both as the .50 Carbine, and as the .50 Spencer) C.M. Spencer for some reason did not like inside lubed bullets, and created an alternate round using a shorter .56 case with a slightly larger Heel type bullet, calling it the .56/.52.  This could be fired in the same chamber as the goverment .56/.50 round.  This latter round really succeeded only in confusing folks, as it does to this day.  The Goverment as well as private buyers perferred the inside lubed .56/.50.

Note there is no powder designation in any of these rounds.  The Spencer rimfires held around .45 grains.  In fact I don't know of any era rimfire rounds that used the standard nomenclature of the later CF rounds.   

That is about as clear an concise explaination as I've ever read ... and spot on