Glock 31: Complete Guide, Review, Specifications, Features & FAQs

The Glock 31 is a full-size semi-automatic pistol chambered in .357 SIG, a cartridge known for its high velocity and distinctive bottleneck design. The model occupies an interesting position in the Glock lineup because it combines the dimensions and general configuration of a full-size Glock with the .357 SIG cartridge.

The Glock 31 has been offered in different configurations over the years, including the Glock 31 Gen 4. Glock’s official documentation lists the G31 as a .357-caliber pistol with a 4.49-inch barrel, a standard 15-round magazine, and a 32 mm overall width.

People researching the Glock 31 commonly search for terms such as Glock 31 Gen 4, Glock 31 357 SIG, Glock 31 for sale, and Glock 31 357. Understanding these terms requires looking at the model’s specifications, generation differences, cartridge characteristics, dimensions, maintenance considerations, and relationship to other Glock models.

This guide provides a factual overview of the Glock 31, including its design, specifications, history, Gen4 characteristics, .357 SIG chambering, general market-price context, common questions, and important considerations for anyone researching this model.

Glock 31 Overview and Specifications

The Glock 31 is classified by Glock as a full-size pistol. Its current official specifications list a 4.49-inch barrel, 8.03-inch overall length, 5.47-inch height, and 1.26-inch overall width. The unloaded pistol weighs approximately 23.28 ounces without its magazine.

Its standard magazine capacity is 15 rounds, while Glock lists optional 10- and 16-round configurations in its technical data. Magazine availability and legality can vary depending on jurisdiction and configuration.

Glock notes that its published technical specifications can change without notice, so current manufacturer documentation should be consulted when exact specifications matter.

Full-Size Configuration

The Glock 31 uses a full-size frame rather than the compact dimensions associated with the Glock 32 or subcompact dimensions of the Glock 33.

This gives the G31 a longer barrel and larger overall profile than its .357 SIG siblings. Glock lists the G32 with a 4.02-inch barrel and 7.36-inch overall length, while the G33 Gen4 has a 3.43-inch barrel and 6.42-inch overall length.

The three models therefore provide different size configurations around the same general cartridge family.

Glock Safe Action System

The Glock 31 uses Glock’s Safe Action system. Glock’s technical documentation identifies this system across the G31 and G31 Gen4 configurations.

The system incorporates multiple internal safety features. Safe firearm handling remains essential regardless of the particular action or safety system involved.

Glock 31 357 SIG: Understanding the Cartridge

The phrase Glock 31 357 SIG refers to the G31 chambered in .357 SIG.

The .357 SIG cartridge was developed around a bottleneck case based on the .40 S&W case, necked down to accept a .357-caliber projectile. Glock’s buyer materials describe the cartridge as a high-velocity round designed for use in a semi-automatic pistol.

The cartridge’s bottleneck design is one of its defining physical characteristics.

Unlike traditional straight-wall pistol cartridges, the .357 SIG case narrows toward the projectile. This gives the ammunition a distinctive appearance and contributes to its identity within the handgun-caliber market.

Velocity Characteristics

The .357 SIG is generally associated with relatively high velocity compared with many traditional service-pistol cartridges.

Glock describes the G31 as being characterized by high muzzle velocity and suitability for longer shooting distances.

Actual velocity depends on ammunition, bullet weight, barrel length, environmental conditions, and testing methodology. Consequently, ammunition-box specifications should be consulted when exact ballistic figures are required.

Cartridge Availability

One consideration when researching a .357 SIG firearm is ammunition availability.

.357 SIG is less common than some mainstream handgun cartridges, so local availability can vary considerably. Ammunition manufacturers have historically produced both practice and defensive loads for the caliber, but availability and pricing change over time.

For owners, checking current ammunition availability and complying with all applicable laws are important parts of responsible firearm ownership.

Glock 31 Gen 4

The Glock 31 Gen 4 introduced several ergonomic changes compared with earlier Glock configurations.

Glock’s official G31 Gen4 documentation identifies the model as a .357 SIG pistol with a modular backstrap system and reversible magazine catch.

The Gen4 configuration retains the fundamental G31 dimensions and caliber while providing additional grip-adjustment and control features.

Modular Backstrap System

One of the key Gen4 characteristics is the modular backstrap system.

The system allows the grip configuration to be adjusted using interchangeable backstrap components. Glock specifically describes this as a way to customize the grip for different hand sizes.

This was a significant ergonomic change from earlier Glock generations.

Reversible Magazine Catch

The Glock 31 Gen4 also features a reversible magazine catch.

This allows the control to be configured for either left- or right-handed operation, according to Glock’s product information.

The feature is particularly relevant when comparing the Gen4 model with earlier versions of the G31.

Gen4 Dimensions

Glock lists the G31 Gen4 at approximately:

• 7.95 inches overall length
• 5.47 inches height
• 1.26 inches overall width
• 4.49 inches barrel length
• 23.28 ounces unloaded
• 15-round standard magazine capacity

These specifications are listed in Glock’s official Gen4 technical data.

Glock 31 Gen 3 vs Glock 31 Gen 4

The comparison between earlier G31 configurations and the Glock 31 Gen 4 is useful for understanding Glock’s development.

The basic characteristics remain familiar: both are full-size .357 SIG pistols with a 4.49-inch barrel and 15-round standard magazine specification.

The Gen4 model introduced ergonomic changes including the modular backstrap system and reversible magazine catch.

The exact configuration of an individual firearm should always be verified using its markings, documentation, and manufacturer information.

Glock 31 Performance Characteristics

The Glock 31 was designed around the performance characteristics of .357 SIG.

Its full-size dimensions provide a 4.49-inch barrel and relatively long sight radius. Glock lists a polymer sight radius of 6.50 inches.

A longer sight radius can make precise sight alignment easier for some users, although practical accuracy depends on numerous factors.

Recoil Characteristics

The subjective recoil of the Glock 31 can vary according to ammunition, bullet weight, grip technique, and individual experience.

The .357 SIG is commonly described as having a sharper recoil impulse than softer-shooting cartridges, while the G31’s full-size frame provides a substantial platform compared with smaller .357 SIG models.

The appropriate way to evaluate recoil is through supervised, lawful range use and proper training rather than relying solely on specifications.

Accuracy

The G31 is designed as a full-size pistol and has a 4.49-inch barrel with a 6.50-inch polymer sight radius according to Glock’s specifications.

Accuracy from an individual firearm depends on ammunition, sights, shooter technique, mechanical condition, and environmental conditions.

Published specifications therefore provide useful context but should not be interpreted as a guarantee of a particular group size.

Glock 31 vs Glock 32

The G31 and G32 share the .357 SIG chambering but occupy different size categories.

Glock identifies the G31 as a full-size model and the G32 as a compact model.

The G31 is therefore longer and slightly heavier, while the G32 uses a more compact configuration.

Glock 31 vs Glock 33

The Glock 33 represents the subcompact member of this .357 SIG family.

Glock lists the G33 Gen4 with a 3.43-inch barrel, 6.42-inch overall length, 4.21-inch height, and standard nine-round magazine.

This creates a clear size progression:

Glock 31 → full-size

Glock 32 → compact

Glock 33 → subcompact

All three models are associated with .357 SIG, but their dimensions and capacities differ substantially.

Glock 31 Price and Market Context

Searches for Glock 31 for sale often relate to the current market value of new, used, discontinued, or law-enforcement-trade-in examples.

Pricing can vary considerably because the G31 has existed in multiple configurations and generations.

Factors that may influence market pricing include:

• Generation
• Overall condition
• Factory configuration
• Sight configuration
• Included magazines
• Original packaging
• Local market conditions
• Ammunition availability
• State and local regulations
• Whether the firearm is new or used

Historical Glock buyer guides provide useful context for older manufacturer pricing. For example, Glock’s 2023 buyer’s guide listed an MSRP of $599 for the G31 Gen4.

That historical MSRP should not be treated as a current retail price. Current pricing can differ significantly depending on the date, seller, market, and firearm condition.

Glock 31 for Sale: What the Search Term Means

The keyword Glock 31 for sale is commonly used by people researching listings for new or used G31 pistols.

From an informational standpoint, several details should be checked when evaluating any firearm listing:

• Exact model designation
• Generation
• Caliber
• Condition
• Included magazines
• Included factory accessories
• Whether modifications have been made
• Applicable transfer requirements
• Local and state restrictions

A listing should also be compared with the manufacturer’s specifications to ensure the advertised configuration corresponds to the actual firearm.

Because firearm laws vary by jurisdiction, legal requirements should be verified with the relevant authorities or a properly licensed dealer before any transaction.

Glock 31 357: Why the Model Is Distinctive

The phrase Glock 31 357 is often shorthand for the Glock 31 chambered in .357 SIG.

The model is distinctive because it combines:

• Full-size dimensions
• .357 SIG chambering
• 4.49-inch barrel
• 15-round standard magazine
• Polymer frame
• Safe Action system
• Glock’s established design architecture

Glock’s official description emphasizes the model’s high muzzle velocity, lightweight construction relative to its size, and large magazine capacity.

Glock 31 Maintenance and Ownership Considerations

Like any firearm, the Glock 31 requires appropriate maintenance.

Owners should use Glock’s official owner’s documentation and maintenance guidance rather than relying exclusively on generalized internet advice. Glock maintains an official library of owner manuals, product information, and safety documentation.

General areas of attention include:

• Keeping the firearm clean according to manufacturer instructions
• Inspecting magazines
• Checking for unusual wear
• Using appropriate ammunition
• Following manufacturer lubrication guidance
• Having mechanical concerns evaluated by qualified professionals

A firearm that develops an unexpected mechanical problem should not be modified or repaired based solely on online instructions.

Glock 31 Common Considerations

The G31’s .357 SIG chambering creates several characteristics that prospective owners and researchers commonly consider.

Ammunition Cost

.357 SIG ammunition can be more expensive or less widely stocked than common handgun cartridges such as 9mm.

Availability varies by region and over time.

Muzzle Blast

High-velocity ammunition can produce a different acoustic and recoil experience compared with lower-pressure or lower-velocity handgun cartridges.

Appropriate hearing and eye protection are essential during range use.

Cartridge Availability

Although .357 SIG remains commercially available, it is not produced at the same scale as some of the most common handgun cartridges.

This can be relevant for people researching long-term ammunition availability.

Full-Size Dimensions

The G31 is a full-size pistol measuring approximately 8.03 inches long and 5.47 inches high with a 1.26-inch overall width.

Its dimensions should be considered when comparing it with compact and subcompact alternatives.

Glock 31 Frequently Asked Questions

What caliber is the Glock 31?

The Glock 31 is chambered in .357 SIG. Glock’s technical documentation identifies the caliber as .357.

What is the Glock 31 Gen 4?

The Glock 31 Gen 4 is the fourth-generation configuration of the G31. It retains the .357 SIG chambering and full-size dimensions while adding features such as a modular backstrap system and reversible magazine catch.

How many rounds does a Glock 31 hold?

Glock lists a standard magazine capacity of 15 rounds for the G31. Its technical information also lists optional 10- and 16-round configurations.

What is the Glock 31 barrel length?

The G31 has a 4.49-inch, or 114 mm, barrel.

How long is the Glock 31?

Glock lists the current G31 at 8.03 inches overall. The G31 Gen4 specification lists 7.95 inches overall length.

How much does the Glock 31 weigh?

The G31 weighs approximately 23.28 ounces unloaded without the magazine. With an empty magazine, Glock lists approximately 26.10 ounces.

Is the Glock 31 a full-size pistol?

Yes. Glock identifies the G31 as a full-size .357 SIG pistol.

What is the difference between the Glock 31 and Glock 32?

Both are .357 SIG models, but the G31 is full-size while the G32 is compact. The G31 has a 4.49-inch barrel and 15-round standard capacity, while the G32 has a 4.02-inch barrel and 13-round standard capacity.

What is the difference between the Glock 31 and Glock 33?

The G31 is full-size, while the G33 Gen4 is a subcompact model. Glock lists the G33 with a 3.43-inch barrel and nine-round standard magazine.

Is the Glock 31 still documented by Glock?

Yes. Glock currently maintains an official G31 product page with technical specifications.

Is the Glock 31 Gen 4 still relevant?

The G31 Gen4 remains useful for understanding Glock’s .357 SIG lineup and Gen4 design features. Glock’s official documentation specifically identifies the G31 Gen4 and provides its specifications.

Final Thoughts on the Glock 31

The Glock 31 is a distinctive full-size pistol built around the .357 SIG cartridge. Its combination of a 4.49-inch barrel, 15-round standard magazine, 8.03-inch overall length, and 1.26-inch width gives it a clear position within Glock’s .357 SIG family.

The Glock 31 Gen 4 adds ergonomic features including a modular backstrap system and reversible magazine catch while retaining the fundamental G31 configuration.

When researching terms such as Glock 31 357 SIG, Glock 31 357, or Glock 31 for sale, it is important to distinguish official specifications from third-party descriptions and current market listings. The model’s price can vary according to generation, condition, configuration, and local market factors, while historical MSRP figures should not be mistaken for current retail pricing.

For anyone studying Glock’s .357 SIG lineup, the G31 provides a useful example of a full-size pistol built around a high-velocity cartridge. Its relationship with the compact G32 and subcompact G33 also demonstrates how the same cartridge can be incorporated into different firearm sizes and configurations.

As with any firearm, users should follow applicable laws, manufacturer instructions, and established firearm-safety practices. Glock’s official resource library provides current manuals, product information, and safety materials for owners and researchers.