Sig Sauer P320 XTEN Review: The Best Polymer 10mm?

by Stephanie Martz

April 7, 2023



The XTEN joins the SIG P320 lineup with their first and only striker-fired 10mm handgun, the SIG P320-XTEN. In this Sig Sauer P320 XTEN review we will go over what SIG did to make this larger caliber handgun modern and fun to shoot, even for small women like myself.

The Full size Sig P320 chambered in 10mm.

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Sig Sauer P320 XTEN Specs

  • Caliber 10mm Auto
  • Action Striker Fired
  • Capacity 15 + 1
  • Trigger XSeries Straight
  • Sights 3 Dot X-RAY3 Day/Night Sights
  • Slide Stainless Steel
  • Frame Polymer
  • Barrel Carbon Steel
  • Barrel Length 5 in
  • Weight 33 oz
  • Safety None

Sig P320 XTEN Background

10mm Auto Pistols are becoming the new hotness mainstream. While hunters have been using them for ages to take down deer and pigs, it hasn’t really caught on in the mainstream firearms market in awhile. The FBI being the closest to getting it there after adopting the cartridge after a 1986 shootout in Miami and the loss of two Federal agents. Later, it was found that many agents just were not good at shooting that round due to the recoil it generated. Even today, people still have a tough time depending on the specific 10mm and the load.

It has still taken a while for the 10mm to reach new heights. The most known 10mm pistol was the Glock 40 or the Glock 20. Holsters were hard to find, you couldn’t mount an optic on it, and honestly they just weren’t fun to shoot. With more companies making these firearms though, more upgrades to the 10mm Auto platform are being made.

SIG took this gun and made it both practical with a polymer X-Series frame and picatinny rail but also juiced it up with their Flat trigger and optics ready steel slide. It is modular following suit of the 320 platform. In short, it doesn’t feel like you are moving up to a 10mm but instead grabbing a P320 and getting a large caliber out of it. This notion is enhanced with ergonomically friendly controls that even my small fingers can reach.

When thinking about how this pistol is to be used, backcountry is where it’s at. 10mm is a very capable round and there are plenty of stories of a 10mm pistol saving someone’s life from a grizzly bear. Whether you are a hunter or hiker that wants protection, you no longer need the heavy and miserable 10mm handgun anymore. The polymer frame lightens this gun up and due to the 320 platform, it fits in normal P320 holsters. Mainstream, meet backcountry.

Sig Sauer P320 XTEN Features

Sig Sauer P320-XTEN Gun Features
1 X-Series Frame

While this is an upgrade for other P320’s, this polymer frame with undercut trigger guard, flat grip sides, stippled grip, large beavertail, and slightly flared magwelll comes already on the gun.

2 Steel 15 Round Mags

Steel magazines allow for heavier and easy to drop magazines. 15 Rounds of 10mm is potent.

3 Optics Ready Slide

The stainless steel slide is optics ready and is cut for a Romeo2 or Trijicon RMR.

4 Modularity

The gun will fit into a X-series holster or holsters that are light compatible. Any P320 FCU will fit in the XTEN.

5 Trigger

The XTEN comes out of the box with an upgraded straight trigger with a pull weight of 5 lbs and 8 oz.

Models and Variations of the Sig P320 XTEN

There is only one option for the XTEN form Sig. However, they do have a few handugns offered in the X lineup.

Sig Sauer P320 XTEN –  Our Take

Shooting Sig P320 XTEN

This review is going to be based off of testing 6 different types of ammunition over multiple days at the range w/ Josh Shaw a USPSA GrandMaster. During these days we grouped, shot drills, and used what we knew about other 10mm pistols to compare. There were some great things noticed about the pistol and some not great things.

The largest thing that can be said about this handgun is that it frankly does not feel like you are shooting a 10mm. This is said with such emphasis that those who didn’t know what kind of firearm this was and SIG not telling them, thought they were shooting a 9mm. Mostly due to the comfort of the X-Series polymer frame with the heavier steel slide, it just accepts the recoil exceptionally.

Accuracy and Reliability

Sig P320 XTEN Target

During one of the range days 6 types of ammunition were shot at 25 yds with a 5 round group. We didn’t mess with pushing the iron sights since they were on paper and I knew I was going to change them out after adding a dot.

Group sizes in order, beginning with the tightest group

  • Sig V-Crown 180gr JHP
  • PMC 170gr JHP
  • Federal HST 200gr HSM 180gr
  • Nosler 180gr
  • Federal Punch 200gr

At 25yds the SIG V-Crown had 4 rounds touching. For a 10mm, I’d say that’s pretty dang impressive.

As far as reliability there were zero malfunctions after 150 rounds with the 6 types of ammunition above. This changed after a squib load from crappy 1776 branded lead free ammo. Not the guns fault, completely the ammunition’s fault. Thankfully it was caught before shooting another round as that next round would not chamber.

The magazines were tight so that will take time to break in.

Ergonomics and Controls

Sig Sauer P320 In The Hand

As far as ergonomics and controls of the gun, remember that I have small hands so the controls on a 10mm can already seem daunting due to reach. However, with the XTEN, I was pleasantly surprised. The finger reached the straight trigger so easily that I could choose were to lay my finger. Usually, I have to kind of play around with using the tip to middle pad however I had room to lay my finger entirely over the trigger due to my first knuckle able to reach it and pull. The slide stop can be pressed without breaking your grip, same for the mag release. While the slide stop is ambidextrous, which is a positive, there is room for improvement.  It only has 3 small ledges, and the paddle is pretty small, making it easy for my finger to slip off of the stop. The mag release shape is nice due to a triangular natural to the thumb grip but that could also have more friction.

SIG built a new Xseries frame for the XTEN with a lot of the same features as any other P320 X series frames such as the undercut on the trigger guard, the flat sides of the grip, and the stippling. The only thing that is missing is the small rectangular weight that can be installed into the grip module on other 320’s. SIG’s website specifically says that this weight is not compatible with the XTEN. Inside the XTEN frame is the cut out for installing it, but there is no weight. Does it need it? Not really, but it is a nice option to have.

Sig XTEN Triger Gauge

The frame and small hands do just fine together due to the flat sides of the grip. The flared magazine well is a very nice touch as is the rail slots for a white light which is absolutely needed in the backcountry environment.

The only other drawback that could be an issue for some shooters is that the large beavertail in the rear of the gun is not removable as it would be for a Glock per say. Some could find this annoying, some could love it. I didn’t mind it as it did help me establish a high grip but the more I shoot it I may start playing around with reducing the sheer size of it.

The Iron Sights

The 3 dot iron sights are a big drawback for this gun. While night sights are nice, the 3 dot design is just not conducive to fast and accurate shooting when it comes to irons. Many shooters, myself included, are moving to a blacked out rear sights and a tritium red front sight. This design acts almost as a red dot and allows your brain to focus on lining up one thing, not three things.

The other issue with these sights is that while this is pushed as a “red dot ready” 10mm firearm, the first thing you have to do when receiving the gun is put higher sights on it to be able to use it with a dot. This means having the proper sight pusher and finding the right sights. Kind of a pain after receiving a red dot ready platform.

Installing a Red Dot

You would think that it being 2023 we have finally caught up to a standard when it comes to red dots and pistols. With many pistols though, it is a hassle finding the correct plate for the correct dot for the correct slide. This was the case with the P320-XTEN as well.

Six P320 XTEN Red Dot

The slide is cut for a Romeo2 or Trijicon RMR. However, plates do not come with the gun nor is there a drop down when purchasing to have a plate included. The footprint for the slide is kind of cool with each indentation for recoil bosses and such, however even though it is cut for the most popular red dot out there, it was a total pain finding a spacer plate for it. In my case, I chose to throw on a Holosun 508T. The footprint allowed the 508T to be screwed in, however there was a ton of space left and SIG does say that a spacer plate should be installed. It’s worth it to note that dudes online are using this optic on the gun without a plate putting all of the recoil into the screws and not the gun. (I hope they don’t have sheared screws due to this) The search for the correct plate on the Legion slide began with only two options being found and some confusion still lingering. I ultimately purchased a SIG P320 w/ R1P / DPP CUT w/ RMR / Holosun Holes – Filler Plate for RMR / SRO / Holosun by CHPWS it’s a mouthful I know. This plate ended up adding some space but there is still a tiny gap behind the optic not making it as tight as a fit as I would have loved, especially with a 10mm.


Overall, the value is pretty good for being under $800 MSRP and getting an upgraded frame, upgraded trigger, and red dot ready slide right out of the box. Purchases do still need to be made for a red dot plate and taller sights.

Sig P320 XTEN Patch

Sig Sauer P320 XTEN Pros and Cons 

  • X-Series Straight Trigger – The flat trigger has a light and clean pull and is able to be comfortable reached and pressed with short fingers.
  • Optics Cut Slide – Comes with a red dot compatible slide cut for the Romeo2 and RMR.
  • X-Series Polymer Frame – The polymer frame accepts recoil and already comes stippled with a flared magwell and a 5 slot rail for a light.
  • 3 Dot Xray Sights – Hate hate hate the 3 dot design on iron sights as it is confusing for the brain. These sights heights are out of the box not compatible with a mounted red dot.
  • Red Dot Plate – SIG does not offer a filler plate with the purchase of the gun and it can be confusing to find one as there are not many options. A red dot should not be used without a proper tight and filled fit on the slide due to recoil from a 10mm.

Report Card


The 3 dot iron sight design and lack of optic plates out there brought this score way down.


Zero malfunctions after 150 rounds with multiple types of ammunition.


While many controls were reachable with small hands, there wasn’t enough grip on the slide stop and mag release.


4 rounds touching with a 5 round group at 25 is enough accuracy to take down an animal (or person) in the back country.


A couple of things need to be purchased after receiving the gun such as an optic plate and higher iron sights however the upgraded trigger, frame, and slide right out of the box is great value for a 10mm under $800.

Sig Sauer P320-XTEN Final Grade

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Reviewed by Stephanie Martz

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Sig P320 XTEN Starter Pack

These three items are must haves for all firearms owners.

  • Eye Protection: Eyes are hard to replace, you need to have eye protection on when shooting. Here are our recommendations for the best shooting glasses!
  • Hearing Protection: Odds are you already are damaging your ears in day to day life before adding shooting to the mix. If you are going to be shooting you need to have good hearing protection.
  • Gun Cleaning Kit: Here is a link to our article on gun cleaning kits you’ll need to keep your firearms maintained.  

Sig Sauer P320 XTEN Gun Deals

Here are a few deals we found on the Sig Sauer P320 XTEN.

Upgrades and Accessories for the Sig Sauer P320 XTEN

For handguns we always recommend a good holster. Safariland makes great holsters and we think we found a great one for you and your Sig XTEN. Check out the Safariland 578 Pro-Fit GLS.

It’s a Grip Lock System holster that fits a variety of handguns, including the P226, Beretta 92, and others.

We also recommend a red dot sight and the appropriate adapter mounting plate. We have a full article on selecting the best red dot sight for the Sig P320.

Finally, you can never have too many spare magazines, its more fun shooting at the range then reloading magazines.

Upgrades and Accessories for the Sig Sauer P320 XTEN

Red Dot Sight

Holosun 508T

Holosun 508T
  • Larger model of red dot from Holosun so it looks and acts better on a large frame gun
  • Side mounted battery slot so that you don’t have to remove the optic to change the battery
  • Has a solar failsafe, power derived from solar will be used if the battery dies.
Buy on Amazon
C&H Precision Weapons Sig P320 Filler Plate
  • Compatible: Trijicon Type I and Type II RMR/SRO and Holosun 407C, 507C, 508T
  • Material: Stainless Steel
  • Accommodates: LCI (Loaded Chamber Indicator)
Check Price
P320 X-SERIES XTEN 10MM Auto Magazine
  • Sig Factory Magazine
  • 15 Round Magazine
  • Steel
Check Price

Best Ammo for Your Sig P320 XTEN

Looking for good deals on your 10mm ammo for the XTEN? We got you covered below. We have both range and defensive ammo for you.

Range Rounds

CCI Blazer 10mm 200 GR FMJ Ammo

CCI Blazer 10mm 200 GR FMJ

Cost Per Round $0.40
Gun Mag Warehouse $0.44
Target Sports USA $0.60

Defensive Ammo

Federal Personal Defense 10mm 200GR HST JHP Ammo

Federal Personal Defense 10mm 200GR HST JHP

Cost Per Round $1.60
Palmetto State Armory $1.84
Target Sports USA $1.70

Other Pistols of its Class to Check Out

We have an entire article on our favorite 10mm handguns. The Glock 40 comes out as the best home defense option, and I think that fits for personal defense in the woods as well..

Editor’s Choice Glock 40: G40 10mm

10mm Glock 40 (model G40)

Glock 40: G40 10mm

A husky Glock chambered in 10mm. NOT a .40 caliber Glock: this is the Model 40.

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How to Care for Your Sig Sauer P320 XTEN

Here are two good videos about cleaning your Sig P320.

MrGunsNGear goes through the full disassembly and cleaning process on a P320.

The second video from Brownell’s, Steve humbly explains an important feature of putting your P320 back together properly, so it functions for you.

Check out the links below for the manufacturer’s website and operator’s manual.


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About Stephanie Martz

Steph is a veteran Small Arms Repairman in the Army and former gunsmith in the Federal LE sector. She is very active in the Precision Rifle shooting community (including the National Rifle League Hunter Series and Quantified Performance Series). Keep an eye out for reloading for newbies tips and equipment DOs and DON’Ts, complete with the WHYs.

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