The Glock G21SF Gen3 is a .45 ACP full-size semi-automatic pistol with a 4.61-inch cold hammer-forged barrel and a 10+1 capacity. It weighs 29.1 oz (approximately 2.4 lbs) with a black nDLC finish, polymer frame, and fixed sights. 
 

Key Specifications 

• Brand: Glock 
• Model: G21SF Gen3 
• Caliber: .45 ACP 
• Capacity: 10+1 rounds 
• Barrel Length: 4.61 inches 
• Weight: 29.1 oz (approximately 2.4 lbs) 
• Finish: Black nDLC Finish 
• Action Type: Semi-Auto Striker Fire 
• Sights: Fixed 
   

Detailed Features 

 
The SF (Short Frame) designation means the grip has a reduced circumference compared to the standard G21, which makes the gun more accessible to shooters who found the full-size G21 grip too large. The Safe Action system uses three independently operating safeties (trigger safety, firing pin safety, and drop safety), all of which disengage on trigger pull. The cold hammer-forged barrel delivers consistent performance across high round counts. Fixed sights are standard; no adjustable rear is included at the factory level. 
 

Usage Scenarios 

 
As a full-size .45 ACP pistol, the G21SF works well for home defense where carry weight isn't a daily concern. Law enforcement and duty use were part of the original design intent. On the range, the fixed sights and predictable Safe Action trigger make it straightforward to train with.

The G21SF Gen3 gets reviewed with the same strengths and caveats as the rest of the Glock .45 ACP lineup. Reliability is universally praised. The platform runs through diverse ammunition without complaint, which is the baseline expectation Glock buyers bring to the purchase. Accuracy gets consistent positive marks from owners who practice regularly.

The SF grip is frequently called out as the reason many buyers chose this over the standard G21. People with smaller or medium hands report a noticeably better fit and improved control. The .45 ACP caliber is appreciated for stopping power in self-defense contexts, though some newer shooters find the recoil heavier than smaller calibers.

Size and weight are the main practical limitations. At 29.1 oz, it's on the heavier end for a carry gun, and the full-size frame rules it out for comfortable daily concealed carry for most people. Aftermarket support is deep, though less focused on this frame size than on the G17/G19 footprint.