8)The 38S&W came first....it is a short roiund that is fatter than the "38 Colt". When S&W developed their new 38 round, they lenthened the "38 Colt" case, and originally creffered to it as the "38 S&W Special". In the late 19th and on well into the 20th Century, the rivalry between Colt and S&W was fierce....so much so that some of the 1950 Target models made by S&W that chambered the "45Colt" cartridge had a barrel mark of "45 Caliber"....they wouldn't put the word "Colt" on their barrel! Likewise, Colt did not like advertising for S&W with their guns either........SAA's were made in "38 Colt" caliber, and after the turn of the century, Colt marked early 1st gen SAA's, chambered for "38 S&W Special" with the "38 Colt & S&W Special" marking, which is where Cimarron got the idea.
Now to further confuse folks, the 38 Colt was originally loaded in the case we now call the "Short Colt", and used a heeled bullet, propelled by 17-or so grains of gunpowder.....which we now call "Black Powder"...the heeled bullet was constucted much like today's 22LR, in that the main section of the slug was the same basic dimension as the outside of the case, and had a small tail section that sat in the case....these were "outside" lubed, meaning the lubricant was on the bullet, like the waxy film on 22's.....the original "38 Colt" was fired from conversions with the standard .375 bore, and later the Lightning '77 DA, which also had the .375 bore.....outside lubed bullets are a mess in general as you get all kinds of crud on the bullet, especially if you drop it in the dirt. As "inside lubricated bullets became more or less standard, with the lube grooves cut into the slug, the "39 Colt" cartridge was modified by lengthening it to cover the lube groove(s)....to compensate for the oversized bores of most "38 Colt" guns, the bullet had a hollow base which would bump up and engage the rifling to put some spin on the slug....lengthening the case allowed the powder charge to remain the same. A properly loaded 38 Colt, using a heeled bullet and the shorter case, is the same basic OAL as a 38 "Long" Colt cartridge....when you use a traditional inside lubed bullet with the 38 "Short" Colt case, you cut down the powder capacity drastically.
The 38 Colt was a more accepted round than the 38S&W, as it was generally a more 'powerful' round.....38S&W always used an inside lubed bullet in that stubby case, so there just wasn't a lot of powder in there.....when S&W designed the 38 "S&W" Special, they took the 38 "long" Colt case, and lengthened it to allow for a few more grains of powder, and more power....but using the same basic case, the owner could use either cartridge in it.....S&W did this again in 1935 when they designed the "357 S&W Magnum" cartridge.
So, hopefully this helps somewhat, but the 38 S&W, and the 38 S&W Special are two distinctly different cartridges.
As a side note, during WWII, S&W made a lot of M&P's (Model 10) in 38 S&W for use by Britan, the Brits liked the cartridge loaded with a 200gr slug......these were called the Victory models, and many came back stateside and were reamed to accept the longer 38 Special cartridge, which doesn't work so well as the cases swell up the length of the original chamber!
If you have a 357 magnum, you can use 38 SPL, 38 "Short" Colt (with an inside lubed bullet), or 38 "Long" Colt....38SPl's can use the last three cartridges, but if it's a "38S&W", that's the round you're stick with.
Personally, I like 45's!