I shared in a story in the Lounge about how I acquired this addition to my collection at the link below, but this post is a little about the pistol itself.
The Sergeant-Major's Colt 1903
The serial number of 440xxx indicates it was made in 1924 and is a "Type III" variant with integrated barrel bushing and 3 3/4" barrel and no magazine safety. It's marked on the slide "calbre .32 rimless smokeless" which indicates it's .32 ACP and the magazine holds 8 rounds. This one has Colt's famous highly polished finish common in that day and factory walnut grips.
Although Colt marketed these as "hammerless", this pistol was actually fired by action of a hammer striking and driving a firing pin into a center-fire cartridge's primer. The hammer was covered by the rear of the slide. The "hammerless" designation was merely an advertising designation pointing out the pistol's particular suitability for concealed carry. Special features include a serrated slide to prevent slippage during manual cycling of the slide, and two safety mechanisms (a grip safety and a manual safety). The grip safety is a spring-loaded piece making up the back strap of the pistol. The grip safety, though not solely restricted to them, was a typical feature of Colt automatic pistols of the period.
So as to indicate a size comparison, I've pictured the Colt 1903 alongside a full size 1911A1.