The Colt Model 1905 is a pivotal firearm in the history of American military handguns and represents a major milestone in the journey toward the legendary Colt Model 1911. Designed by John Moses Browning, the Colt 1905 introduced the powerful .45 ACP cartridge and was one of the first semi-automatic pistols to seriously compete for a spot as the U.S. military’s standard sidearm.

🔫 Overview

• Name: Colt Model 1905 Automatic Pistol
• Designer: John M. Browning
• Manufacturer: Colt’s Patent Firearms Manufacturing Company
• Caliber: .45 ACP (Automatic Colt Pistol)
• Magazine Capacity: 7 rounds
• Action: Short recoil, locked breech, semi-automatic
• Production Period: 1905–1912
• Total Production: Approximately 6,100 pistols
• Notable Feature: First Colt semi-automatic to use the .45 ACP cartridge

📜 Historical Context

The Colt Model 1905 was developed in response to the U.S. military’s dissatisfaction with the .38 caliber pistols it had previously adopted, including revolvers and earlier semi-automatics like the Colt 1900 and 1902 models chambered in .38 ACP.

📌 Why the Shift to .45?

• During the Philippine–American War (1899–1902), U.S. troops reported that .38 caliber sidearms lacked stopping power against Moro fighters.
• The military began demanding a return to a larger, more powerful cartridge—specifically, a .45 caliber.

This led Browning to develop the .45 ACP cartridge and redesign his semi-automatic pistol around it, resulting in the Colt Model 1905.

🔧 Design Features

1. .45 ACP Chambering

• First semi-auto pistol to chamber the now-famous .45 ACP round, which Browning developed in conjunction with Union Metallic Cartridge Company (UMC).
• This cartridge became the standard U.S. military pistol round for most of the 20th century.

2. Short-Recoil Operation

• The 1905 used a short-recoil, tilting barrel system—an evolution of the system first used in the Model 1900.
• This core operating principle would remain in nearly all of Browning’s later pistols, including the M1911, Hi-Power, and others.

3. Hammer and Safety

• Spur hammer (exposed)
• No manual thumb safety or grip safety, which would come later in the 1911 design

4. Magazine and Feed System

• 7-round detachable box magazine
• Single-stack design
• Loaded from the bottom (magazines were not interchangeable with later 1911s)

🧪 Military Evaluation

The U.S. Ordnance Department began testing the Colt Model 1905 shortly after its release. Key points include:

• The Model 1905 was submitted to U.S. Army trials in 1907.
• Despite enthusiasm for the .45 caliber, the pistol’s design was still seen as incomplete from a combat perspective.
  • No manual safety
  • No grip safety
  • Still some reliability issues under rough field conditions

As a result, the 1905 was not adopted as the official service pistol—but it laid the groundwork for continued development.

🔍 Transition to the M1911

The feedback from trials of the Colt 1905 informed Browning and Colt engineers on necessary improvements:

• In 1907, the U.S. Army issued contracts for military trial pistols, now called the Model 1907, which were modified 1905s with:
  • Grip safety
  • Heavier frame
  • Other experimental features

🔫 Collector Significance

The Colt 1905 is a highly collectible pistol due to its:

• Historical importance
• Limited production (just over 6,000 made)
• Role as the first .45 ACP semi-auto pistol
• Link to the legendary M1911