Sig Sauer P320

7.8 score
(TheGearHunt) score (7.8)/10

Our TheGearHunt score is based on 3 different factors: Editor's rating after in-depth testing. User ratings submitted on this page Overall score from the "reviewmeter" based on reviews across the web the weight of each factor is: 40% editor rating 15% user ratings 45% reviewmeter.
Editor rating: 7.0 / 10
User's rating: based on 14 user ratings
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Sig Sauer P320 Review Facts

The Sig Sauer P320 is patterned after the striker-fired version of the P250. It is a single and double action, modular framed gun. The P320 has the same barrel, magazine, and grip as the P250.

There is a compact and full-size version in .40 S&W and 9mm. A .357 Sig version is on the way. The frame, that is not really a frame, is what makes the P320 a modular gun. Inside a polymer grip module is a serialized stainless steel chassis 'frame'.

On the right of the plastic grip is a window where the serial number can be seen. The compact and full-size grips are available large, medium, and small. It is possible for the .357 Sig, .40 S&W, and 9mm serialized chasses to be exchanged. Only Sig fanboys and police departments are likely to buy all the spare components to do so.

Editor's Pros & Cons
  • 3-Point-Takedown Safety System
  • Customizable
  • Durable and lightweight polymer frame
  • Interchangeable grips
  • Customers complained about the rear sight coming loose
  • Unattractive aesthetics

Primary Use

It will be a contender for agencies in the market for law enforcement striker-fired guns. The P320 was built as a duty gun. The company had no model that agencies that were moving to striker guns would consider.

The Sig Sauer P320 has all the features anyone searching for a defense pistol wants or needs. The P320 does feel good in the hand and shoots. Shooting full-size 9mm-chambered guns is fun.

The Sig Sauer P320 can easily whack steel at 50 yards. The pistol is accurate enough for competition. It easily outshoots most shooters. The large trigger blade is deeply curved. Until the shooter is acclimated to the trigger, accuracy can be hindered.

The high-bore axis causes the gun to feel somewhat like a ray gun. It is comfortable in hand. The plastic frame is warm even when the weather is cold. The grip panel feels like skateboard tape without sand.

Subdued stippling works better than it appears. It may be necessary to feel it in hand and fire it to appreciate the P320. The trigger is a suitable striker-fired trigger. There is no stacking, and the weight is decent.


The barrel of a full-size Sig Sauer P320 is 4.7 inches. A compact version has a barrel that is 3.9 inches.

Stock Options

The ATF considers the serial number to the ‘gun.’ Everything else is regarded as a part. The slide and grip frame do not have a serial number. The mags and slides can be changed so that all common calibers can be shot from the pistol.

Resizing the gun to the shooter’s hand is possible by using a few panels to change the grip. Sig refers to them as Caliber X-Change kits. Kits are available in Subcompact, Compact, and Full-Size.

There are caliber kits for .357 Sig, .40 S&W, and .380 ACP. The kits include the proper magazine for the grip size and caliber, grip module, and new slide. Because magazines and grip frames are shared with the P250, the grip width circumference and size of the gun can be tailored by changing the plastic grip frame.

The grip of the pistol is marked on the butt and above the accessory rail on the right side of the gun. A designation of ‘Full Medium’ means the grip frame is full-size and the grip size is medium.

The grip of the compact version is short. Sig claims the pistol is more adaptable and ergonomic than any gun in the class. A tester disagrees. He feels the M&P, S&W, and Glock grips are more ergonomic.

Being able to replace a grip module with a different size is not the same as having interchangeable backstraps. The lack of backstraps that are interchangeable is a negative aspect for law enforcement and civilians.

Even though the pistol has a replaceable modular frame, some departments require an ‘armorer’ to replace the frame because disassembly beyond field stripping is needed rather than swapping out backstraps.

There are striker-fired guns that have different sizes of backstraps included. Extra grip modules for the Sig are separate purchases. There are several plastic frames available to tailor the width of the grip.


It weighs 29.4 ounces when not loaded.


Siglite night sights are standard on all P320 models. They are steel sights that have three-dot tritium inserts. Sig has a standard lockable case that houses the Sig Sauer P320. The case includes a holster made of injection-molded polymer.

There are cutouts for two 17-round magazines. The Sig is held at a slightly forward angle in the holster is cheap to make and provides added value. The Sig Sauer P320 fits in a holster designed for the P250.

It has an oversize trigger guard, cutouts on the frame that allow a reticent magazine to be stripped out, standard night sights, and a tactical rail. A red dot sight is installed. It is accomplished by locking the slide back, rotating the takedown lever clockwise, and then sliding the pistol’s upper half.

It is best to have an empty magazine inserted when replacing the slide. The slide lock is lifted and moving the slide rearward and rotating the takedown pin clockwise is easier.


It has a capacity of 17 + 1 in 9mm and 14+ 1 in .40. About two rounds are sacrificed in the compact version, depending on the caliber. Two steel Mec-Gar magazines come with the pistol. The P320 functions and fires all plinking and hollow point ammunition feed through it into a ragged hole.


The mantra of the Sig Sauer Sauer P320 is ‘simple is better.’ There are no controls except a magazine release, takedown lever, and an ambidextrous slide stop and release. With easy-to-follow instructions found in the owner’s manual, the triangular magazine release can be reversed.

The triangular mag release is surprisingly ergonomic. The trigger is smooth and consistent. It is available in a small bladed or standard, short reach design. The trigger pull of the pistol is advertised between 5.5 and 7.5 pounds. One tester measured the pull to be 7.5 pounds, which he feels is too heavy.

He did like the length of pull. The total travel length that includes taking up the slack is only 0.4 inch. Without taking the slack into account, the trigger pull length and reset is only .25 inch, which is excellent.

The short trigger pull makes it shoot quickly. Because the trigger pull is so short, it feels like the pull requires only six pounds of force. Short trigger pulls feel lighter than longer ones that weight the same. That fact is the reason the overtravel stop exists. The sight has less opportunity of being disturbed when pulling the trigger that has a short pull length.

The shooter can shoot quickly when needed. The trigger is steel. The trigger mechanism contains no polymer. The metal-on-metal contact makes The trigger pull consistent due to the metal on metal contact. The slide of a striker-fired gun has to be worked between every pull of the trigger for it to be recocked.

The trigger clicks each time even though the gun does not have double strike capability. The trigger will click every time it is pulled, even when the striker is forward. The striker is pre-cocked inside the slide. Sig uses the term ‘partially pre-tensioned.’

A block is used to cock the striker as the slide advances. When the trigger is pulled the block moves and allows striker movement. Saying the striker is somewhat pre-tensioned is a bit misleading — the block that holds the striker rotates in the front.

It moves in an arc. Technically, it moves slightly rearward. When the striker is pulled backward, it moves less than an inch. With the almost undetectable rearward movement, Sig can claim the Sauer P320 is not a single-action weapon.

Very few police departments authorize law enforcement agents to carry a single action weapon. They can carry the P320. In reality, single-action pistols have short trigger pull. There is no stacking with the consistent trigger pull.

Stacking is the trigger getting heavier as the shooter pulls it until it breaks. It is a common occurrence in older designed pistols, especially those with double action triggers. One tester complained of the magazine not dropping free for reloading both when barehanded or wearing gloves.

The problem may be due to the size of his hands. A meaty palm may prevent the mag from dropping free. He had no problem with the mag jamming or coming out.

A tester found the magazine stiff at first and required downloading by two. The solution was having the magazine loaded for two weeks. It could then be loaded to capacity.


The Sig has a Nitron finish slide. The slide has forward cocking serrations and traditional lines. Both sides and the front and back of the frame have fine texturing. Appearances can be deceiving. The pistol is more grippy and aggressive than it looks. The texture is part of the molding. It is not mechanically etched after the molding process.

The small detail is hard to see, but the tiny edges are sharp. One tester claims it is a rarity to find a polymer framed pistol that is aesthetically pleasing. He likes the traditional Sig slide lines, but not the clunky frame.

A tester, who is a fan of Sig pistols, was excited by the announcement the company was producing a striker-fired gun. He was hoping the design would not feature the high-bore offset common to Sig pistols.

Bores set high, produce a muzzle rise, and the recoil is noticeable. Unfortunately for him, Sig chose to build a FrankenSIG made from existing P250 parts. It is clever engineering, but the tester felt Sig missed an opportunity.

Larger slide serrations would be an improvement. Shooters with sweaty hands found racking the slide troublesome. Deep slide serrations found on an S&W M&P could serve as an example.


The safety features of the Sauer P320 include a trigger bar, firing pin, and others that make the pistol as safe as the other Sig line pistols. The single piece trigger is something no other striker-fired pistol has.

The trigger pack design is a one-piece rather than the two-piece hinged trigger that is widely used in the M&P and Glock design which houses a safety feature that controls and operates without shoot input.

Sig heavily promotes the safety system known as the ‘Three-Point Take Down' of the P320. The magazine is removed, and the slide locked down to the rear before it is disassembled. The trigger does not have to be build to dismantle.

The feature sets the pistol apart from other striker fired weapons. The safety factor for novice officers or gun owners who have little safe weapon handling skills is increased.

A spokesman for Sig tells us the company will make versions with a trigger tab or a thumb safety available because of the number of agencies that feel they are a must. They will be for specific law enforcement orders. They will be available overseas also but not in the U.S., at least for a while.


The small metal gun is a bit pricey. The MSRP is $679 for full-size Sig Sauer P320s having night sights.

Key Features

* Black Nitron finish
* Capacity for full-length 17 + 1
* Capacity for compact 14 + 1
* Fixed iron sights
* Full-length version barrel length is 4.7 inches
* Compact version barrel 3.9 inches
* Striker-fired action with short recoil
* Weighs 29.4 ounces, unloaded

Bottom Line

Sig is the semi-automatic gold standard. It is known for double and single action fired guns. Entering the striker-fired market is a welcome sight for a stagnant market. The P320 is a viable replacement for Glock pistols used for general shooting and CCW.

Striker-fired guns have an advantage people love. Increased internal safeties and a consistent trigger pull are primary reasons elite military units, police agencies, and armed citizens switch to striker-fired guns.

The striker-fired gun mechanisms are easy to produce, assemble and simple for armorers to fix. Striker guns are cheaper than traditional firearms. The significant difference between other Sig Sauer double stack pistols and the P320 is the P320 uses a striker, and others use hammers.

It offers the reliability and quality of a Sig Sauer striker system that is tried and true, a feature that makes the P320 a novel gun. The pistol is an innovated design.