SIG SAUER P320 SubCompact Pistol in 9mm Review

by Col (Dr) Ben Findley*
Col Findley reviews the modality and shooting performance of the SIG SAUER P320 SubCompact Pistol .

SIG SAUER P320 SubCompact Pistol in 9mm Review
SIG SAUER P320 SubCompact Pistol in 9mm

The Sig P320 series of pistols are very adaptable and overall known as very good performing handguns.

There are 4 versions of the Sig Sauer striker-fired P320: the Full-Size, Carry, Compact, and SIG SAUER P320 SubCompact Pistol, all in 9mm Luger. I have shot and own all of them at my own expense. There are other calibers available in .40 S&W, .357 SIG, and .45 ACP. I am impressed with the handgun’s adaptability, modularity, reliability, and quality.

The pistol’s modularity and flexibility features are especially worth attention. You should know that Sig Sauer is not paying me for my review or opinions here, nor reducing the gun price or providing it or the ammo, so I am not on their payroll and sincerely want to give my objective evaluation to help you.

SIG SAUER P320 Pistol : Adaptability, Flexibility, & Modularity

SIG SAUER P320 Handgun ModularitySIG SAUER P320 Handgun Modularity
SIG SAUER P320 Handgun Modularity

With the P320, one single pistol can become a full-size, compact, or sub-compact handgun and each with 3 different grip sizes.

With all P320 models, shooters can swap out the pistol’s barrel, frame, trigger and slide assembly to customize the gun. Sig Sauer recognized the significance of a striker-fired pistol, introduced these hammer-less guns, and they are popular primarily because of the nature of the trigger operation and modularity features. The P320 can be changed into whatever frame size, barrel, and caliber the shooter wants. Among the components needed for the P320 to complete a caliber change is a cartridge-specific magazine and the conversion kit. The backstrap does not need to be changed, since the entire polymer grip module can be easily changed for a comfortable, customizable, and solid grip if desired. The stainless steel frame rests inside the grip module, which is serialized, and they use identical, serialized, modular fire-control (trigger) groups.

Other non-serialized P320 parts can be ordered and shipped direct to you without going through an FFL Dealer. With its modular grip frame and removable fire control assembly pioneered by SIG SAUER, the P320 is customizable to any hand size or duty requirement. The P320 can quickly be converted from a Full-size to a Carry pistol, etc. Slide and barrel conversions allow the P320 to change between calibers and barrel lengths as well. This unique modular design offers the shooter the ultimate in flexibility to change calibers, sizes, and fit. Small, medium, and large polymer grip modules ensure a comfortable and optimal fit for the widest range of hand sizes.

My 320 full-size and compact mags work in my 320 sub-compact.

Sig Sauer P320 Sub-Compact 9mm Specifications*:

  • Action: Double Action Striker-Fired Semi-Auto
  • Caliber: 9x19mm (Also available .40 S&W, .357 SIG, .45 ACP)
  • Capacity: 12+1 rds (Also available 10 rds, 10 rds, 6 rds); Magazine Catch repositions to either side
  • Grip Width: 1.06” (3 Glass-Reinforced Grip Modules in small, medium & large sizes))
  • Weight: 24.9 oz. with Empty Mag
  • Length: 6.67”
  • Height: 4.67”
  • Barrel: 3.55”
  • Slide: Nitron High-Strength Stainless Steel; Front & Rear Cocking Serrations; Slide-Catch Lever functions from both sides
  • Frame: One-Piece Stainless Steel Frame; Black Polymer Grip Module- Available in various sizes (Also available Flat Dark Earth & Two-Tone Flat Dark Earth Colors)
  • Sights: High Contrast or SIGLITE Night Sights in Different Heights
  • Other: 2 Trigger Lengths- Standard & Short; Removable & Interchangeable Fire Control & Grip Modules; No tools or trigger manipulation required for Take-Down; Uses Compact 15 & Full-Size 17 mags
  • MSRP: $628 (Black-Standard)

* Per Sig Sauer, weights and dimensions are approximate. Specifications subject to change without notice. Prices vary by dealer & options.

Live Inventory Price Checker

SIG SAUER P320 SubCompact Pistol Selected Features:

The P320 Sub-Compact is built with a stainless steel frame and slide and is covered in a Nitron finish for rust resistance.

One interesting feature is that the trigger options include a smooth-faced or a tabbed-trigger safety, with the latter similar to Glock pistols. I prefer the smooth trigger face which for me is more comfortable to shoot, especially in an extended range session. The tabbed-trigger safety is simply an add-on feature for shooters who prefer to have a positive, tactile feel of the trigger prior to the trigger beginning engagement.

The trigger tab safety does not replace or alter the striker safety’s function or design, as it is only an add-on option for the trigger.

I like the P320 grip angle and comfort which give me more control, more so than with my Glocks. Also, the all-metal rails of the P320 in a solid stainless-steel frame give me greater stability and I like its metal trigger over the polymer.

For all P320s pistols, I like that the mags and holsters are interchangeable (some with the X grip adapter) and with Sig P250 models. The X grip adapter allows you to use the compact mags for 15 capacity or the 17 capacity ones. The X grip adapter is a little piece of rubber that fills the gap when you’re using larger-capacity mags. With the SIG SAUER internal safety system, the P320 has no external safety or decocking lever to snag or hang up on the draw and I like that. The SIGLITE night sights are very nice and the reversible magazine release makes the P320 completely ambidextrous.

It also has an ambidextrous slide release. There are also nice front and rear cocking serrations.

SIG SAUER P320 SubCompact Pistol Trigger and Reset:

SIG SAUER P320 SubCompact PistolSIG SAUER P320 SubCompact Pistol
SIG SAUER P320 SubCompact Pistol

Trigger press on all P320 pistols in the line are generally weighted at 5.5 to 6.5 pounds, giving shooters a consistent trigger press. For me, the sub-compact trigger is very smooth, short, and soft, is not a long press, is consistent, needs no improvement out of the box, and I can easily press it. Although I measured the sub-compact trigger press with my Lyman Trigger Gauge to be between 6.0 and 6.5 pounds before I shot it, I understand that it is not necessarily the trigger weight, but the smoothness of the whole action of the trigger assembly that makes the difference. With more firings, it will soften. Overall, the stock trigger is very good and I believe that it is as good as the $150. kits some have put in Glocks and M&P’s, including myself. I could handle the recoil easily and it was mild for such a small concealed carry gun.

With a partially pre-tensioned striker, I found the P320 to have a short, crisp trigger press with a quick, pronounced reset right out-of-the-box. I really like the reset and could clearly feel and hear it.

SIG SAUER P320 SubCompact Pistol Internal Safety System:

The P320 sub compact features a unique internal safety system, standard on all SIG P320 models with these features:

  • Striker Safety- Prevents the striker from releasing until the trigger is pressed.
  • Disconnect Safety- Prevents the gun from firing when out of battery.
  • 3-point Take-Down Disassembly Safety System- Only allows disassembly if slide is locked back, mag removed, and take-down lever is simply rotated, without pressing the trigger or using tools.
  • Takedown is prohibited without removal of the magazine.
  • Takedown is prohibited without slide locked to the rear.
  • Rotation of takedown lever allows disassembly without tools and without pressing the trigger.

SIG SAUER P320 SubCompact Pistol Some Advantages:

  • Grip Modules (in 3 sizes).
  • Fire Control (trigger) Modules- Interchangeable.
  • Night Sights; Standard Steel Sights.
  • Rounded, No-Snag Trigger Guard & Edges- for concealability & comfort.
  • Very Thin Width and Contoured Frame.
  • Easy and Quick Disassembly.
  • Nice Capacity of 12 +1 for 9mm.
  • Front & Rear Slide Serrations- for easier Slide Racking.
  • All Steel Guide Rod, Magazines, & Slide Rails.
Sig Sauer P320 Sub-Compact 9mm Grip Module - Medium SizeSig Sauer P320 Sub-Compact 9mm Grip Module - Medium Size
Sig Sauer P320 Sub-Compact 9mm Grip Module – Medium Size
Sig Sauer P320 Sub-Compact 9mm Fire Control ModuleSig Sauer P320 Sub-Compact 9mm Fire Control Module
Sig Sauer P320 Sub-Compact 9mm Fire Control Module
Here is a side-by- side comparison of the SIG SAUER P320 SubCompact Pistol (on left) and the Full Size 320 handgun.Here is a side-by- side comparison of the SIG SAUER P320 SubCompact Pistol (on left) and the Full Size 320 handgun.
Here is a side-by- side comparison of the SIG SAUER P320 SubCompact Pistol (on left) and the Full Size 320 handgun.
Here is a size comparison of the Sig 320 Sub-Compact (top left) to the Smith-Wesson M&P 9C; the Ruger Sr9C, and the M&P Shield.Here is a size comparison of the Sig 320 Sub-Compact (top left) to the Smith-Wesson M&P 9C; the Ruger Sr9C, and the M&P Shield.
Here is a size comparison of the Sig 320 Sub-Compact (top left) to the Smith-Wesson M&P 9C; the Ruger Sr9C, and the M&P Shield.

SIG SAUER P320 SubCompact Pistol Range Performance:

The small-size grip frame for the sub-compact fit my medium-sized hand nicely, with my pinkie finger just partially dangling. However, I was able to maintain a good solid grip without adjusting my grip. I was very surprised for such a small and lightweight gun the recoil was light and easily managed. I sincerely enjoyed shooting the gun. While I only had about 100 rounds of Federal American Eagle 115 grain FMJ ammo to test it at the range, the P320 sub-compact performed flawlessly and I have no doubt it will handle any modern JHP ammo just as well. It is so smooth to operate, and I really like the trigger and definitive reset point. To me, it is very comparable to my Smith & Wesson M&P 9 Compact, especially regarding the 12 capacity and similar barrel length, although lighter in weight and shorter in total length.

Most shooters recognize that ANY gun should be “broken-in” with about 400-500 rounds or so fired for a better evaluation of its performance and reliability. So remember that I did not shoot that many rounds. The gold standard is for you to actually shoot and handle the gun and learn your accuracy with it and things about it, like I did. For me, ACCURACY and RELIABILITY are the most important factors. Closely related to that is the handgun’s trigger, so I focused on these features.

The SIG 320 Sub-Compact 9mm shot extremely well and I was accurate with it in rapid fire; e.g. see below my first magazine of 12 rounds that I fired at 7 yards.

Sig P320 Sub-Compact 9mm - Range TestSig P320 Sub-Compact 9mm - Range Test
Sig P320 Sub-Compact 9mm – Range Test

Performance & Handling Summary for SIG SAUER P320 SubCompact Pistol in 9mm:

(1) At close distances of 5, 7, and 10 yards, I found that the accuracy and reliability were very good for the 320 sub-compact. My groups were all 4.0 inches or less for the first time I ever fired the gun “out of the box” drawing from the holster it came with in the hard case. I used a Modified-Isosceles Standing Stance, a two-handed grip, and shot 115 grain FMJ. I had no malfunctions nor stoppages and could handle the recoil easily.

Sig P320 Sub-Compact 9mm in Hardcase with 2 Mags, Holster, Lock & ManualSig P320 Sub-Compact 9mm in Hardcase with 2 Mags, Holster, Lock & Manual
Sig P320 Sub-Compact 9mm in Hardcase with 2 Mags, Holster, Lock & Manual

(2) The trigger press out of the box averaged 6.2 pounds without modification with my Lyman Electronic Trigger Pull Gauge. For comparison out-of-the-box, my Sig 938 has a 7.1 pound press; the Springfield XDs has a 7.2; my Ruger SR9C, Glock 19, M&P Shield, M&P 9C, and Taurus G2 all have about a 6.0 press; my Springfield EMP a 5.8 press; my Springfield XD9 Mod.2 a 6.5; my Ruger LC9s has a 5.2 press; and my Colt XSE Commander (.45), Kimber (.45), Sig (.45), S&W Pro 1911 (9mm) and Taurus (9mm) 1911s have about a 4- 4.5 pound press each. I know my brain is my best safety, but I do not want a too light trigger for concealed carry, nor do I want a heavier one either. All of these are close to my desired range.

(3) The trigger was smooth, crisp and very good. It had a short travel distance and short, identifiable reset, so I could get off quick follow-up shots easily and keep on target easier. The reset was very identifiable.

(4) The striker-fired trigger made for consistent and reliable shooting with pretty much the same press each time. It was just a slightly harder press that I am accustomed to, since I mostly shoot 1911s and single actions.

(5) The Siglite night sights were easily identifiable and I like them.

(6) The weight of the gun was about 26 ounces with a loaded magazine in place and this is manageable for concealed carry. I like a slightly heavier gun for better recoil control, comfort, and accuracy.

(7) The 9mm was just the right caliber for me for carry and I strongly prefer it, as you probably know from the reasons in my other articles. So the P320 Sub-Compact met this requirement.

(8) The width of the 320 SC measured 1.06 inches and this was slim and very nice for me. The grip angle was fine and it felt very comfortable in my hand, especially when shooting. To me, width is a key CC factor and this width was perfect.

(9) The capacity of the 320 SC is 12+1 and this gives me mental comfort, especially when dealing with multiple bad guys and when compared to some of my other CC guns with less capacity. The mag release can be repositioned to either side for an ambidextrous advantage.

(10) The height of the 320 SC was 4.67″, compared to my XD-9 SC-Mod 2 at 4.75″, my M&P-9C at 4.3 inches, my SR9C at 4.6 inches, my EMP at 4.8 inches, my Glock 19 at 5.0, my HK P30 at 5.4, and the M&P Shield at 4.6 inches. These are all acceptable to me for concealed carry, with the smaller numbers being more advantageous.

SIG SAUER P320 SubCompact Pistol Bottom Line:

I definitely RECOMMEND this Sig Sauer P320 Sub-Compact 9mm pistol for concealed carry, based on the above criteria and information. This gun will be in my concealed carry rotation among my 6 Concealed Carry guns.

Incidentally, my wife liked the comfort and accuracy of the 320 sub-compact. She said it was fun to shoot this gun and we both want to shoot it more.

This snag-free, thin, sub-compact can be used in IDPA in the Backup (BUG) Division, since it meets the requirements with less than a 3.6″ barrel and unloaded gun weight with mag of less than 29 ounces. I hope this review has helped you. In my opinion, it is an excellent striker-fired pistol for concealed carry with its great capacity of 12 rounds, minimal recoil, acccuracy, and excellent trigger, but decide for yourself based on your desired features, your tradeoffs, and your use and needs. TRY IT BEFORE YOU BUY, like any possible handgun purchase.

Continued success!

Further information: or call 866-345-6744.

Photos by Author and Sig Sauer.

* This personal opinion article is meant for general information & educational purposes only and the author strongly recommends that you seek counsel from an attorney for legal advice and your own personal certified weapons trainer for proper guidance about shooting & using YOUR firearms, self-defense and concealed carry. It should not be relied upon as accurate for all shooters & the author assumes no responsibility for anyone’s use of the information and shall not be liable for any improper or incorrect use of the information or any damages or injuries incurred whatsoever.

© 2016 Col Benjamin Findley. All Rights Reserved. This article may not be reprinted or reproduced in whole or in part by mechanical means, photocopying, electronic reproduction, scanning, or any other means without prior written permission. For copyright information, contact Col Ben Findley at [email protected].

Col Benjamin FindleyCol Benjamin Findley
Col Benjamin Findley

About Ben Findley:

“Col Ben” is retired with 30 years service in the U.S. Air Force, with joint services Special Ops duty and training, and is Air Force qualified as “Expert” in small arms. Ben is an experienced NRA-Certified Pistol Instructor, NRA Range Safety Officer, and FL Concealed Carry License Instructor.

Ben recently wrote the book “Concealed Carry and Handgun Essentials for Personal Protection” with 57 comprehensive Chapters about concealed carry and handgun principles, techniques, and tips for both experienced and new shooters.

His reference book is endorsed by several organizations and is available on his website at Contact him at [email protected].

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