Description
Glock 21 Gen 4 45 ACP Night Sights
Glock 21 Gen 4 45 ACP Night Sights
The Glock 21 Gen 4 .45 ACP with Night Sights is a full-size, striker-fired semi-automatic pistol chambered in .45 ACP (45 Auto). It is the fourth-generation version of Glock’s high-capacity .45 caliber pistol, combining the proven Glock 21 platform with Gen4 ergonomic improvements and factory-installed night sights.
Overview
| Feature | Details |
|---|---|
| Manufacturer | Glock Ges.m.b.H., Austria |
| Model | Glock 21 Gen4 |
| Caliber | .45 ACP / .45 Auto |
| Generation | Gen 4 |
| Action | Striker-fired |
| Operating system | Glock Safe Action® |
| Frame | Polymer |
| Slide | Steel |
| Barrel length | 4.61 inches |
| Capacity | 13 rounds standard |
| Included magazines | Usually 2 × 13-round magazines (varies by package) |
| Sights | Factory night sights |
| Finish | Glock corrosion-resistant slide finish |
| Country of manufacture | Austria (many U.S. models use U.S.-made components) |
Technical Specifications
| Specification | Measurement |
|---|---|
| Caliber | .45 ACP |
| Barrel length | 4.61″ (117 mm) |
| Overall length | 8.07″ |
| Height | 5.51″ |
| Width | 1.34″ |
| Slide width | 1.12″ |
| Weight unloaded | 26.28 oz |
| Weight with empty magazine | 29.28 oz |
| Weight loaded | Approximately 38.8 oz |
| Trigger pull | Approximately 5.5–6.3 lb |
| Magazine capacity | 13+1 rounds |
Gen 4 Improvements
The Gen4 Glock 21 introduced several upgrades over earlier Glock 21 models.
Modular Backstrap System
The frame includes interchangeable backstraps that allow the shooter to adjust:
- Grip circumference
- Trigger reach
- Hand fit
This helps accommodate different hand sizes.
Rough Textured Frame (RTF)
The Gen4 frame texture provides:
- Better grip retention
- Improved control with sweaty or wet hands
- More secure handling under recoil
Reversible Magazine Release
The Gen4 magazine release:
- Is larger than previous generations
- Can be reversed for left-handed shooters
Dual Recoil Spring Assembly
The Gen4 recoil system uses a dual recoil spring assembly designed to:
- Reduce felt recoil
- Improve durability
- Handle the .45 ACP cartridge’s recoil impulse
Night Sights
The night-sight version includes factory-installed illuminated sights.
Typical features:
- Tritium inserts
- Three-dot sight picture
- Low-light visibility
Advantages:
- Faster sight acquisition in poor lighting
- Better than standard polymer Glock sights
- Useful for defensive applications
When evaluating a used Glock 21 Gen4, check the brightness of the tritium inserts because night sights gradually dim over many years.
Barrel & Accuracy
Barrel:
- 4.61-inch Glock polygonal barrel
- Right-hand twist
- Designed for reliability and long service life
Typical accuracy:
- Around 2–4 inches at 25 yards depending on ammunition and shooter skill
The full-size frame and relatively heavy slide help make the Glock 21 Gen4 comfortable to shoot despite the powerful .45 ACP cartridge.
.45 ACP Cartridge
The .45 ACP is one of the most recognized handgun cartridges in history.
Typical loads:
- 185 grain
- 200 grain
- 230 grain
Common characteristics:
- Large bullet diameter
- Moderate velocity
- Manageable recoil compared with many high-pressure cartridges
- Strong performance with modern defensive ammunition
Magazine System
Standard Glock 21 Gen4 magazines:
- Capacity: 13 rounds
- Double-stack design
Compatible magazines include:
- Glock 21 Gen3/Gen4 magazines
- Glock 21 extended magazines (where available)
Handling Characteristics
The Glock 21 Gen4 is a large-frame pistol designed around the .45 ACP cartridge.
Advantages
✅ High .45 ACP capacity
✅ Very reliable operating system
✅ Excellent durability
✅ Comfortable recoil for a .45
✅ Factory night sights
✅ Customizable grip size
✅ Large aftermarket support
Limitations
❌ Large grip circumference
❌ Heavy compared with 9mm pistols
❌ Less convenient for concealed carry
❌ Ammunition cost is generally higher than 9mm
Common Uses
Duty / Professional Use
The Glock 21 has been used by various law enforcement agencies because of:
- Reliability
- Simplicity
- High .45 ACP capacity
Home Defense
The G21 Gen4 is popular for:
- High capacity
- Easy operation
- Low maintenance
Range Use
The full-size frame makes it comfortable for:
- Training
- Practice sessions
- Defensive shooting drills
Glock 21 Gen4 vs Glock 21 SF
| Feature | Glock 21 Gen4 | Glock 21 SF |
|---|---|---|
| Caliber | .45 ACP | .45 ACP |
| Barrel | 4.61″ | 4.61″ |
| Capacity | 13 rounds | 13 rounds |
| Grip | Adjustable backstraps | Reduced circumference frame |
| Recoil system | Dual spring | Earlier recoil system |
| Best for | Adjustable fit | Smaller hands |
Maintenance
Recommended care:
- Clean barrel and slide rails periodically
- Lubricate Glock lubrication points
- Inspect recoil spring assembly
- Check magazine condition
- Replace worn springs as needed
Glock pistols are known for very long service lives when properly maintained.
Used Purchase Inspection Checklist
For a used Glock 21 Gen4 with night sights:
Slide
✔ Check finish wear
✔ Inspect slide rails
✔ Verify smooth cycling
Barrel
✔ Check rifling condition
✔ Look for corrosion or damage
Frame
✔ Inspect:
- Slide rails
- Accessory rail
- Magazine well
- Grip frame
Night sights
✔ Confirm tritium brightness
✔ Check sight alignment
Overall Assessment
The Glock 21 Gen4 .45 ACP with Night Sights is a powerful, reliable, full-size pistol that combines Glock’s proven design with useful Gen4 upgrades. It offers 13-round .45 ACP capacity, improved ergonomics, and factory low-light capability, making it well suited for duty use, home defense, and serious range work.
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