Made in various calibers, the .45 Colt version with a 5½" barrel, was adopted by the U.S. Armed Forces as the Model 1909.

It was made in the popular large caliber revolver cartridges of the day: .38-40, .44-40, .44 Russian, .44 Special, .45 Colt, .450 Boxer, .455 Webley, and .476 Enfield.

Beginning in 1899, combat reports from the Philippines campaign showed that the .38 caliber bullets repeatedly failed to stop Moro fighters, even when shot multiple times at close range.

The Model 1909 was also chambered for the .45 Calibre Revolver Ball Cartridge, Model of 1909, which was dimensionally similar to the original .45 Colt cartridge, but it has a rim that is .03 inches (0.76 mm) wider for a more positive ejection with the use of the swing-out cylinder's star extractor.

[6] It also played a key role in the Army's decision to adopt the new .45 ACP M1911 Colt pistol, only two years later in 1911.

[3] The M1917s saw action again during World War II, when it was issued to "specialty troops such as tankers and artillery personnel".

[13] He later modified two .45 Colt New Service revolvers in the same manner,[14] and was known to carry the pair in his front pockets.

Fitz Special revolvers are made by taking any standard size Colt revolver, shortening the barrel to two inches, shortening the ejector rod, bobbing the hammer spur, rounding the butt, and removing the front half of the trigger guard.

Reshaping the hammer and the butt allows the gun to be drawn quickly with little risk of the weapon snagging on clothing.

[15] Historians believe that somewhere between 40 and 200 Fitz Specials left the factory, made from various Colt revolvers, by Fitzgerald himself.

Colonels Rex Applegate[17] and Charles Askins were proponents of the Fitz Special,[16][3] and it would become a popular after-market conversion for many gunsmiths.