The Glock G45 MOS is a 9mm compact pistol with a 17+1 capacity, 4.02-inch barrel, and a factory-cut slide for mounting red dot optics without adapters. It runs Glock's Gen 5 improvements including the nDLC-finished steel slide, polymer frame with interchangeable backstraps, and the Glock Marksman Barrel (GMB). 
 

Key Specifications 

• Caliber: 9MM Luger (9x19 Para) 
• Action: DAO (Double Action Only) 
• Capacity: 17+1 rounds 
• Barrel Length: 4.02 inches 
• Weight: 30.34 oz (1.89 lbs) 
• Finish: Black polymer frame, nDLC-finished steel slide 
   

Detailed Features 

 
The MOS (Modular Optics System) cut on the slide accepts a range of red dot sights using included adapter plates, with no milling required. The Glock Marksman Barrel uses an improved rifling profile for better accuracy than earlier Glock barrel generations. Interchangeable backstraps let you adjust the grip circumference to fit different hand sizes. 
 
Safety systems include trigger safety, firing pin safety, and drop safety, all passive. There is no manual thumb safety. Fixed sights come installed for use without an optic. The nDLC finish on the slide handles corrosion and wear well under regular carry conditions. 
 

Usage Scenarios 

• Home Defense: 17+1 capacity gives meaningful firepower at home. 
• Competitive Shooting: The optics-ready slide and GMB barrel support accuracy-focused builds. 
• Everyday Carry: At 1.89 lbs the G45 is heavier than a subcompact but manageable for IWB carry for most users.

The G45 draws consistently positive feedback for its ergonomics and reliability. Users who find the full-size G17 a bit long and the compact G19 a touch small often land on the G45 as the right fit. The factory MOS cut is a practical advantage for anyone who wants a red dot; the adapter system works and the available footprint options cover most common optics.

Glock's reliability reputation holds up in discussions about the G45. Users regularly report trouble-free function across a range of 9mm loads, which matters for a duty or defensive gun.

On the critical side, the weight comes up for users comparing it to smaller carry pistols. Trigger opinions split predictably; many find it acceptable, competitive shooters sometimes want a lighter or crisper reset. Aesthetic options are limited compared to some competitors. Pricing is occasionally flagged relative to other 9mm optics-ready pistols, though most see the G45's track record as justifying the cost. The 17+1 capacity is consistently viewed as a strong point.