As many Glock blogs as we’ve written, you’d think we would have written one about the .357 Sig bullet. Well, today is the day we discuss 2 of the 3 pistols chambered in .357 Sig. One of the biggest misconceptions about the Glock 31 and 32 is that they shoot a .357 Magnum. We will explain what a .357 Sig is and how it’s different than a .357 Magnum, to begin with, and then get into the Glock 31 and Glock 32. Glock 31 and Glock 32 are very similar with minor differences in barrel, length, overall length, and weight. Although anytime someone reads “.357” they think of a magnum bullet that brings with it added weight and recoil, these 2 Glocks are much more practical than you’d ever think.

What is a .357 Sig?

A .357 Sig was created by Sig Sauer and Federal ammunition as a specialized law enforcement bullet that can fire from a semi-automatic platform and replicate the power of a .357 Magnum. In actuality, the .357 Sig is much closer to the 9.19mm than it the .357 Magnum bullet. As you can see with the bullet diameter in the tables below, the .357 Sig has a neck diameter of 9.68 mm and a length of 28.9mm. Essentially the .357 Sig is a .40 S&W bullet bottlenecked down into a 9mm casing that has the power very close to the .357 Magnum. The felt recoil of the .357 Sig is much closer to the .40 S&W than the 9mm or .357 Magnum. The biggest issue with the .357 Sig is the price of the bullets are more expensive than both .40 S&W and 9mm, so it becomes difficult to practice with such exuberant cost.

What’s The Difference Between a .357 Sig & .357 Magnum?

The .357 Sig is a rimless bullet, which means the base diameter and the rim diameter are the same to improve the feeding and extraction of the bullets and casing. It’s also bottlenecked, which helps with a more reliable feed for higher caliber rounds than straight walled casings. As you can see below the .357 Magnum is longer, can hold more gun powder, but has less pressure than the .357 Sig. However, even with less maximum pressure, the .357 Magnum will normally have more muzzle velocity and energy than the .357 Sig. The only exception that I’m aware of is the DoubleTap FMJ-FP, which is shown in the chart below.

 

.357 Sig .357 Magnum
Parent case 10mm Auto .38 Special
Case type Rimless, bottleneck Rimmed (R), straight
Bullet diameter 0.355 in (9.02 mm) .357 in (9.1 mm)
Neck diameter 0.381 in (9.68 mm) .379 in (9.6 mm)
Base diameter 0.424 in (10.77 mm) .379 in (9.6 mm)
Rim diameter 0.424 in (10.77 mm) .440 in (11.2 mm)
Rim thickness 0.055 in (1.40 mm) .060 in (1.5 mm)
Case length 0.865 in (21.97 mm) 1.29 in (33 mm)
Overall length 1.140 in (28.96 mm) 1.59 in (40 mm)
Case capacity 19.6 gr H2O 26.2 gr H2O
Primer type Small pistol Small Pistol Magnum
Maximum pressure (C.I.P.) 44,240 psi (305.0 MPa) 35,000 psi (240 MPa)
Muzzle Velocity 1,350 ft/s (410 m/s) 125 GR Federal FMJ 1,450 ft/s (440 m/s) 125 JHP Federal
Muzzle Energy 506 ft-lbs (686 J) 583 ft-lbs (790 J)
Muzzle Velocity 1,450 ft/s (440 m/s)125 GR  DoubleTap FMJ-FP

Glock 31 Gen 4

Now that we have a better understanding of what a .357 Sig is and what it feels like, we can get into the Glock 31. At 8.03″ overall the Glock 31 is not going to be able to be used as a concealed carry pistol. The Gen 4 comes with 3 15-round magazines with 2 interchangeable backstraps to accommodate different hand sizes. The Glock 31 has a phenomenal positive reset for rapid shooting and a short travel of only 2.8″ on the stock trigger. This pistol is made for law enforcement and can be used as an open carry pistol for those who want more power and weight. I know many guys who carry this pistol as their hunting pistol to defend themselves against predators in the mountains or woods. The muzzle velocity and energy from the .357 Sig is comparable to the .357 Magnum, which will give you more accuracy at further ranges than any 9mm you pistol you have.

Specs:

Length (Overall) 204 mm | 8.03 inch
Slide Length 186 mm | 7.32 inch
Width (Overall) 32 mm | 1.26 inch
Slide Width 25,5 mm | 1.0 inch
Height incl.Mag. 139 mm | 5.47 inch
Line of Sight (Polymer) 165 mm | 6.50 inch
Line of Sight (Steel) 164 mm | 6.46 inch
Line of Sight (GNS) 163 mm | 6.42 inch
Trigger Distance 72 mm | 2.83 inch
Trigger Pull Weight 28 N/ 6.29 lbs of force
Weight w/ No Magazine 660 g | 23.28 oz
Weight w/ empty magazine
740 g | 26.10 oz
Weight w/ loaded magazine
940 g | 33.16 oz
Caliber .357 Sig
Safety Safe Action
Magazine Capacity 15/16
Barrel Length 114 mm | 4.49 inch
MSRP $500.00

Pros:

  • Very powerful with great stopping power and energy
  • For such a powerful round, the trigger pull weight is light (6.29 lbs)
  • Excellent price
  • A 6.5″ line of sight offers a long enough sight picture to quickly gain target identification

Cons:

  • Sights are accurate, but I recommend buying aftermarket night sights
  • Ammo is incredibly expensive
  • I believe aftermarket grips are essential for both the Glock 31 & 32
  • The very loud operation can be damaging to your hearing

Where Can I Buy The Glock 31?

  1. Palmetto State Armory
  2. Gun Broker
  3. RK Guns

 

Glock 31 Gen 4 .357 Sig Pistol – PG31502

 

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Glock 32 Gen 4

The Glock 32 Gen 4 is very similar to the Glock 31 with minor differences in height, weight, recoil, and length. It has the same overall and slide width as the Glock 31, but it’s almost a 1/2″ shorter to offer more versatility. The Glock 32 has a higher felt-recoil than most other Glocks, including the .40 S&W pistols, such as the Glock 35. I like the shorter trigger distance on the Glock 32 and the trigger pull weight. As a police officer, this gun is great, but most LEO’s are moving toward the 9mm for a much softer recoil and smaller frame. The muzzle velocity is incredibly high in this pistol, so it’s not for beginner shooters or shooters with smaller hands. For the most part, the ammo is very expensive and the overall cost of ownership is much higher than the majority of all other Glocks.

Specs:

Length (Overall) 187 mm | 7.36 inch
Slide Length 174 mm | 6.85 inch
Width (Overall) 32 mm | 1.26 inch
Slide Width 25,5 mm | 1.0 inch
Height incl.Mag. 128 mm | 5.04 inch
Line of Sight (Polymer) 153 mm | 6.02 inch
Line of Sight (Steel) 152 mm | 5.98 inch
Line of Sight (GNS) 151 mm | 5.94 inch
Trigger Distance** 71,2 mm | 2.80 inch
Trigger Pull Weight 28 N/ 6.29 lbs of force
Weight w/ No Magazine 620 g | 21.87 oz
Weight w/ empty magazine
690 g | 24.34 oz
Weight w/ loaded magazine
860 g | 30.34 oz
Caliber .357 Sig
Safety Safe Action
Magazine Capacity 13/14/15/16
Barrel Length 102 mm | 4.02 inch
MSRP $500.00

 

Pros:

  • Very powerful with great stopping power and energy
  • For such a powerful round, the trigger pull weight is light (6.29 lbs)
  • Excellent price
  • Almost the same size as a Glock 19, which makes it able to use as a CCW

Cons:

  • Sights are accurate, but I recommend buying aftermarket night sights
  • Ammo is incredibly expensive
  • I believe aftermarket grips are essential for both the Glock 31 & 32
  • Heavier recoil than the Glock 31
  • Very loud operation

 

Where Can I Buy The Glock 32?

  1. Palmetto State Armory
  2. Gun Broker

 

Glock 32 Gen 4 .357 Sig PG3250203

 

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Winchester 357 Sig PDX1 Defender

The Winchester Defender PDX1 is one of the most trusted bullets in the Winchester arsenal and the official bullet of the F.B.I… The .357 Sig PDX1 Defender has an expansion that is 1.5 times the original diameter of the bullet for maximum damage. The Notched Jacket is designed to expand into 6 uniform segments upon impact for consistent performance. The Winchester bonding process welds the jacket to the lead core for enhanced penetration and weight retention upon impact. In short, this bullet is going to absolutely destroy its target with maximum penetration and uniform expansion. I would use this bullet as my main carry ammo for either the Glock 31 or 32.

 

S357SPDB Box Image

 

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Prvi Partizan

Some people may automatically turn their nose down at an ammunition manufacturer located in Serbia, but this is the most affordable ammunition for .357 Sig ever made. This is great practice ammo because it’s still the 125 Gr as your normal carry ammo and has an even high muzzle velocity of 1542 fps versus the 1350 fps. This ammo is almost 60% less per round and comes in a box of 50 rounds. Please don’t confuse affordability with being cheap, because Prvi Partizan is a reputable company with almost 100 years of business. With how expensive .357 Sig bullets are, this is a perfect bullet to save money and practice with.

Prvi Partizan .357 SIG FPJ 125 gr 50 Rounds Ammunition - PPH357S

 

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