The 38 Super is a very good round for self defense and small game.
Here is a link to the best reference site for the 38 Super on the web:
http://38super.net/
If you go here...
http://www.midwayusa.com/38-super/br?cid=21664
and here...
http://www.ammunitiontogo.com/index.php/cName/pistol-ammo-38-super-auto
you can see some of the commercial ammo available for the 38 Super. If you plan ahead it's not hard to find ammo.
It was said earlier that most commercial ammo is downloaded to 9mm velocities for the 38 Super and this is true (about 1100 fps with a 130 gr. pill). Makes for decent practice stuff. It's also true that Wilson Combat, Buffalo Bore, Double Tap, Cor-Bon and a couple of others load the round closer to it's full potential (they run about 1350 fps with a 125 gr. jhp).
1350 fps from the 5" barrel of a 1911 is about what the 125 gr. .357 magnum gets from a 4" revolver barrel, if it actually gets that. So it ain't a bad round for self defense.
On the original question of why it isn't more popular...that's an essay in itself as it takes up the history of handgunning in the U.S. But real briefly...
In 1898 Colt wanted a contract with the U.S. military for a semi automatic pistol. So they got Browning to develop one and a round for it. As the Army was using a 38 caliber revolver round at the time JMB developed a 38 acp round for the new gun which was the Model 1900 Military. It was a semi rimmed cartridge. The gun was his first design to use two parallel links to allow the barrel to tilt some. The round fired a 130 gr. jacketed bullet at 1300 fps. It was the most powerful semi automatic pistol in existence by ft. pds of energy. A title it held till the 10mm came along.
The round was too powerful for the design and soon battered the slide badly and broke a few parts in the gun. So the round was down loaded to 1100fps. In 1928 Colt chambered the round in the 1911 and boosted the velocity back up to 1300 fps. The gun was called the
Colt Super 38. Before long folks took to calling the round 38 Super.
Long story short...law enforcement in the U.S. used revolvers back then and the use of the 1911 in 45acp was very limited in law enforcement circles. Less so the 38 Super. The U. S. was a nation of wheelgunners till the 1970s-1980s. Until after WWII no major American manufacturer other than Colt produced a semi pistol in a major service caliber.
The 38 Super was used a little by the OSS during WWII in Europe. Thailand, Indonesia and a few other places adopted it as a military round. It was popular in Mexico and Latin America where both the 9mm and 45acp were banned from civilian use as military rounds. Still is legendary in Mexico.
There was virtually no jhp ammo made for semi-automatic pistols till the late 1970s in the U.S. so the defensive advantage of ammo was with revolver rounds.
The 38 Super led a quiet existence till the 1980s when a pistol shooter brought a 1911 to an IPSC match loaded with 38 Super in a compensated gun. They made major easily and cleaned everyones clock with a gun with so little recoil that recovery time was cut to about nill. The 38Super came to rule in that roost and did so till the mid 1990s or so when they lowered the qualifications of what made major. 38 Super still has a powerful presence in the Bianchi Cup.
Anyway 38 Super is a niche round, a legendary niche round for those who know, but niche.
You get 38 Super because you like how it does what it does. It doesn't do things other rounds don't. It's how it does it that is interesting.
tipoc