The Glock 39 Gen 3 is a subcompact striker-fired pistol chambered in .45 GAP. The .45 GAP (Glock Automatic Pistol) cartridge was developed to deliver .45 ACP-equivalent performance in a shorter case that fits a compact frame. The G39 measures slightly over six inches overall with a 3.43-inch barrel and weighs 24.18 oz unloaded. Capacity is 6+1 rounds. The finish is black gas nitride and the sights are standard fixed Glock sights. 
 

Key Specifications 

• Model: G39 
• Type: Semi-Auto Pistol 
• Caliber: .45 GAP 
• Action: Safe Action / Striker-Fired 
• Capacity: 6+1 rounds 
• Barrel Length: 3.43 inches 
• Weight: 24.18 oz (1.5 lbs) 
• Finish: Black Gas Nitride 
• Sights: Fixed Glock Sights 
   

Detailed Features 

1. Subcompact Dimensions: The G39 is sized close to the Glock 26/27 platform but chambered in .45 GAP, which gives more cartridge energy in a similar-sized package. 
2. Safe Action System: Three passive safeties (trigger safety, firing pin safety, and drop safety) operate simultaneously without a manual safety lever. 
3. Textured Grip with Finger Grooves: Gen 3 Gen grip texture and finger groove design. 
4. 6+1 Capacity: The subcompact .45 GAP platform holds 6+1 from the flush magazine. 
    

Target Audience 

Concealed carry shooters who specifically want a .45-caliber subcompact. The G39 is a niche choice: .45 GAP ammunition is less common and more expensive than 9mm, but buyers willing to accept that get a genuinely compact .45 ACP-equivalent pistol. 
 

Usage Scenarios 

1. Concealed Carry: Subcompact size fits IWB or pocket holsters; the caliber provides .45-class performance. 
2. Home Defense: 6+1 rounds of .45 GAP is adequate for most defensive scenarios. 
3. Backup Weapon: Compact enough to use as a backup for law enforcement carrying a larger primary.

The Glock 39 Gen 3 .45 GAP draws a small but specific following, and owner discussions reflect that niche status.

Concealment is the consistent positive. Owners who specifically wanted a compact .45-caliber pistol find the G39 fills that role well. The Glock platform reliability and the Safe Action system are assumed positives that most owners don't need to discuss at length.

The .45 GAP caliber is the central topic in nearly every discussion. Owners who chose the G39 have already committed to the caliber, but they regularly mention that magazine supply and ammunition availability are more limited than for .45 ACP or 9mm. Finding carry-weight hollow points sometimes requires ordering online rather than picking them up locally.

The 6+1 capacity is frequently compared unfavorably to compact 9mm pistols in the same size class, which can hold 10-15 rounds. This is the most common reason cited for not choosing the G39.

Ergonomics get standard Glock praise: consistent, predictable, functional. The Gen 3 grip texture and finger grooves are a matter of personal taste. Some shooters prefer Gen 4 or later grip options.

Aftermarket support is more limited than for more popular Glock models. Holster availability is the most frequently mentioned gap.