Glock 31 Review and Buyer’s Guide

Glock 31 Gen 4 .357 Sig Pistol isolated in white background

Glock 31 Gen 4 .357 Sig Pistol – PG31502

Glock is a brand name synonymous with both crime, and crime-fighting. With over two-thirds of law enforcement incorporating its use as a service weapon, one can’t ignore its sleek, easy-to-carry design and accurate shooting style.

Advances in technology over the last half-century have spoiled gun enthusiasts, providing options that fill everyone’s needs. New and improved cartridges, lightweight frames, and more comfortable to carry models are all details firearm manufacturers are in mad competition with one another over. 

The Glock 31 isn’t a new model by any means, but the improvements through the last few decades have been kind. Take a look at our own Glock 31 review to determine if it’s a handgun you might need to add to your collection. 

Glock and the .357 Cartridge Fun Facts

  • Glock is a young company compared to its top competitors, but is one of the best-selling firearms in the world.
  • The Glock 31 was created to provide a platform to the .357 Sig which was introduced after the infamous 1986 Miami FBI Shootout.
  • The .357 Sig has a velocity of 1440 feet per second-which measures above the speed of sound. 
  • The above has led to a number of highway patrol agencies to depend on the Glock 31 or comparable .357 Sig models as a duty option despite the continued popularity of the 9mm. 
  • Glocks do not have a manual safety. Rather, they have three mechanical safeties: a trigger safety, a firing pin safety and a drop safety for a quicker, more accurate draw.

Glock 31 History and Overview

Founded in 1968 in Austria by a businessman who also happened to be a polymer excerpt, Gaston Glock knew practically nothing about firearms, but wanted to address the future needs of weaponry for military and law enforcement personnel. He began manufacturing military products in the 1970s and by the early 1980s had introduced the semi-automatic Glock service pistol. The lightweight polymer frame and the developed SAFE ACTION® System revolutionized the pistol market with a first of its kind design that had no manual safety to provide instant shooting- all while protecting against accidental discharge. 

Glock Model 31 Introduction

PG Glock 31 focus on bullet

As mentioned above, after the horrific shootout in Miami in 1986, it became clear that law enforcement needed to level the playing field and required a more powerful and dependable firepower. The answer to this was duplicating the .357 Magnum round into a higher carrying capacity that didn’t limit users to only 6 rounds. It also resulted in a higher energy and flatter trajectory option. 

Glock answered with the development of the Glock 31 which was capable of feeding 15 rounds in a smooth shooting, easy to grip, dependable handgun. This is a powerful firearm that gives you the shooting power needed in a higher-capacity package. It is lightweight and provides interchangeable grip backstraps to customize the overall feel. Plus, the larger magazine release button is incredibly efficient. 

What to Consider Between the Glock 17 vs Glock 31 

PG Glock 31 and magazine

Although this is truly a niche market, especially for the everyday shooter, it is a popular one. Dimensionally, the Glock 31 is identical to the Glock 17, the first Glock to chamber a 9mm, and the difference between the two cartridges is a mere 0.06 millimeters. However, you get more energy on target and better trajectory- all things you want and need in a self-defense weapon. 

Because of this, it is a great choice for concealed carry with little to no change in comfort, accuracy, and ease of draw. If you are already familiar and comfortable with the Glock 17 series, all you need is a new handgun and ammo- drastically reducing train time for muscle memory and target acquisition. Even holsters will fit them both with no issue. 

Obviously, there will be increased recoil with a .357 caliber vs 9mm, and if you plan on using it for concealed weapon competition and shooting tournaments you’ll need to be prepared to make adjustments for this. Otherwise, with only 1 ounce of weight difference, you won’t have much else to worry about. 


PG Glock 31 comparison

When I mention it’s a niche market, I’m not kidding. Despite being an option for various law enforcement agencies, 9mm weapon choices are the weapon of choice due to convenience and familiarity despite the heavier firepower the .357 offers. Plus, the 9mm platform is popular across various tried and true manufacturers, allowing people the option to better meet a more customized fit. 

On that note, Glock also provides another option to chamber the .357 as well: the Glock 32 which provides a more compact design and shorter barrel in case you are turned off by the overall size for conceal carry- but are intrigued by the power it provides. It offers a little less velocity, but definitely gets the job done. 

Glock 31 Features & Benefits

Hoding a PG Glock 31

Despite the fact there are many 9mm series to pick and choose from for all types of carry styles, the Glock 31 still fits into a popular niche that makes it an ideal weapon. Personally, with my smaller frame it is a larger piece for me to comfortably carry concealed, but certainly makes a decent open carry choice, and is a dependable self-defense choice for the home. 

Size-wise, I prefer a small caliber option with a narrow handgrip, although the interchangeable grip backstraps of the Glock 31 gen 4 makes it comfortable to shoot for a wider variety of shooters. Since I live in a state that recognizes extended domain, the firearm makes a perfect choice for such a situation. 


Length: 8.03 inch

Slide Length: 7.32 inch

Width (Overall): 1.26 inch

Height w/ Mag.: 5.47 inch

Trigger Pull Weight: 6.29 lbs of force

Magazine Capacity: 15/16

Barrel Length: 4.49 inch

Caliber (and Swapability)

PG Glock 31 magazine and bullet

As described a few times, the 31 was designed specifically to help make a .357 caliber more useful in high-pressure situations. The fact that it is still manufactured and sells out regularly highlights the continued popularity of the rounds. 

What is unique about the G1ock 31 gen 4 is that you can also swap out the barrel for a Glock 22 gen 4 and modify it to shoot a .40 S & W. This makes it an even larger choice for concealed carry,  but still bumps it up as a formidable self-defense option and also a fun choice for the range. 

Safe Action System

PG Glock 31 focus

The SAFE ACTION® System is what made Glock rise in the ranks of popularity and quality to begin with. This idea removes the manual safety and replaces it with a revolutionized safety system located in the trigger that protects against accidental discharge all while providing almost instantaneous use- saving valuable time when needed. This is exactly why the Glock name is synonymous with law enforcement as it provides them a better response time when under fire. 

Of course, other gun manufacturers have come up with various answers to compete with this, but Glock is still considered the safest option for well-handled firearms. Personally, I like the feature, but since I do not carry a Glock I have to stop myself from reaching for the manual safety which has become a muscle memory reaction.

Interchangeable Grip Backstraps

This is a winning feature for me that I wish all manufacturers would adapt. Not everyone has the same size grip, and anyone with a smaller hand, women especially, run into the problem of a wide grip that will quickly become sore while shooting certain size guns. Being able to change the back straps to accommodate grips is a great way to provide personalized comfort. With that being said, the standard grips are incredibly compact to fit a wide range of hand sizes, including a smaller grip – like I have. I find it higher in quality and comfort compared to other model .357 Sig capable firearms. 

Magazine Capacity 

PG Glock 31 Magazine

The magazine capacity runs hand in hand with the caliber size, as the entire model was created to accommodate more rounds of a more lethal caliber. It is capable of handling 15 + 1, making it formidable in self-defense scenarios. Plus, it is very nice to not have to reload as often on the range. 

Weight Comparison

The polymer and steel Glock design makes them a popular lightweight choice, and the fact this model is only .06 ounces heavier than their 9mm model says a lot. Since I almost exclusively shoot compact, lower-caliber firearms, it is a heavier feel for me at 33.2 ounces loaded (26.1 w/ mag unloaded). However, I actually prefer a handgun with a little heft, and personally stay away from the lightest models to help reduce recoil and reacquire a target more quickly. 


holding a PG Glock 31 in the hand

The standard polymer sights that come with the gun are effective, but are underwhelming. The beauty of any Glock is how easy it is to customize with a variety of sight options, as well as other accessories to make your shooting experience more personal. Glock offers traditional white dot sights or glow in the dark sights. 

Trigger Pull

With a trigger pull of only 6.3 pounds of force, Glocks are known for the lighter touch to help make them more effective in shooting scenarios. In fact, my go-to, the compact Smith and Wesson 9mm M&P Shield has a 6.5 lb trigger force- which makes the Glock 31 a smoother pull on a heavier firearm. And a fun choice to shoot with!

Recoil Comparison

With the stopping power this thing has, you definitely feel the recoil. This is partially why having a grip that fits your hand is so important- to help avoid putting undue pressure against the joint and tendons where your pointer finger meets your thumb. 

What this model does have, is a new recoil spring design that was created to help take some of the force of the energy release. SInce I don’t have an earlier model to compare to, I’ll have to take their word for it. But what I did notice was, as with other Glock models, the shooting is smooth and concise, and re-acquiring a target is easy to do even with the added force. I found it to handle well, and fire accurately over and over again. 

What People Are Saying

There is a reason why the Glock 31 continues to be a popular firearm and holds its own alongside other .357 Sig models. It is a dependable, easy-to-shoot, and lightweight choice that has gathered nothing but praise through the years. 

You’d be hard-pressed to find any criticism unless it was of a personal nature, and I couldnt dig up any problems with the firearm model across a wide variety of community shooting forums. I’m sure the occasional issue arises, but Glock has a great warranty program

To Wrap It Up

Although the Glock 31 isn’t going to be a contender for my own personal concealed carry firearm, it is definitely a firearm I like having available for both self-defense purposes and for range shooting. It is a powerful, smooth option that is comfortable to fire and incredibly accurate. 

Of course, I always suggest getting your hands on a variety of guns to shoot prior to purchase- but I guarantee this is a model you will want to find a use for even if it isn’t a top contender for your immediate needs. 

We’d love to hear what comments you might have below, and, as always- please share!