When Jefferson "Keno" Wilson's Automatic Colt Pistol was introduced, smokeless gunpowder was less than 20 years old.  The 20th Century was just around the corner and Colt Patent Firearms Manufacturing was looking to the future.  The semiautomatic pistol was still in its infancy and Colt wanted in. 

That's when Colt went to John Browning, a brilliant and prolific firearms designer.  In 1900, using Browning’s patents, they introduced a new semiautomatic pistol they called the Automatic Colt Pistol, Browning’s Patent or .38 Caliber Colt Automatic Pistol.  (Today, collectors call it the Model 1900)  This was Colt’s first semiautomatic pistol. 

The pistol they produced had a six inch barrel and held seven shots.  It fired a new cartridge, the .38 rimless smokeless, designed for use in this pistol.  (The round is called .38 ACP today).  It also had an unusual safety.  The rear sight was pivoted on a pin.  In the down position it locked the firing pin in place and prevented firing.  In the up position, the firing pin was unlocked, ready to fire. 

Experience in the field showed the sight safety arrangement to be clumsy to use and in some cases unsafe. 
The spur hammer was also criticized.

Colt decided to make changes in response to reports from the field.  The rear sight safety was removed and replaced with a dovetailed rear sight as commonly seen today.  The hammer was changed from a spur to rounded.  They also took the opportunity to change from smooth wood grips to checkered hard rubber.  The changeover to the new model took place around December of 1901. 

Colt did not change the name at that time but in late 1902 renamed it a Sporting Model, Caliber .38.  (Collectors call it the Model 1902)  Production ended in 1907.

Keno Wilsons pistol was made in early 1902.  It has the dovetailed rear sight, rounded hammer and hard rubber grips of the improved model. Police regulations at the time required firearms be carried concealed, so we don’t know when or how long he carried this pistol.  What is known is the pistol was handed down through subsequent chiefs until it was donated to the San Diego Police Historical Association Society by then Chief Jerry Sanders in 1999. 

Today, the pistol and its holster are on display at the San Diego Police Museum. 
Keno Wilson served the SDPD from 1899 - 1926. He served as Chief of Police from 1909 - 1917. He is widely regarded as SDPD's best Chief.