The Glock G39 Gen 3 is a subcompact .45 ACP pistol built around concealed carry. At 6.49 inches overall and 24.1 ounces loaded, it's one of the smaller .45 ACP options on the market while still running the standard Glock operating system. 
 

Key Specifications 

• Manufacturer: Glock 
• Model: G39 
• Caliber: .45 ACP 
• Barrel Length: 3.4 inches 
• Total Length: 6.49 inches 
• Total Height: 4.17 inches 
• Weight: 24.1 ounces (1.5 pounds) 
• Capacity: 6 rounds 
• Frame Material: Polymer 
• Slide Material: Forged Steel 
• Action Type: Double Action 
• Sights Front/Rear: Fixed (1-Dot Front / 2-Dot Rear) 
• Safety Features: Trigger/Firing Pin/Drop Safety 
   

Detailed Features 

The G39 keeps the .45 ACP caliber in a genuinely small package. The 3.4-inch barrel and short grip make IWB carry practical, though the tradeoff is a 6-round magazine, low even for a subcompact. The polymer frame is textured for grip and holds up well to daily carry wear. 
 
Three internal safeties (trigger, firing pin, and drop) are standard Glock fare. Fixed 1-dot front and 2-dot rear sights handle target acquisition without additional parts. 
 

Usage 

The G39 appeals to carriers who want .45 ACP in a package small enough to disappear under a cover garment. The 6-round limit is a real constraint, but extended magazines are available for shooters who want more capacity in a home-defense or range context.

The G39 gets discussed mainly by .45 ACP loyalists who want a compact carry gun without switching caliber. Size and concealability are the dominant positives. The gun is legitimately small for a .45, and most users find it hides well.

The 6-round capacity comes up constantly as a drawback. Many users work around it with a flush 6-rounder in the gun and an extended 8- or 9-round spare, but it remains a real limitation compared to 9mm subcompacts that carry 10+ rounds. Some users question whether .45 ACP is necessary in a small defensive gun, while others maintain stopping power justifies the tradeoff, a debate without a clean resolution.

Glock's reputation for reliability carries over and users rarely report malfunctions. Ergonomic feedback is typical for the platform: the grip suits average-sized hands, some smaller-handed users find it a bit thick, and aftermarket grips and trigger options are available for customization. The price is generally considered fair given the Glock name and parts availability.