Sig Sauer P320 : A Closer Look At The Army’s New Gun

By Tom McHale
Tom gives us our first up-close detailed look, at the Army’s new Sig Sauer P320 handgun and it’s ground breaking modular design.

Sig Sauer P320 :The Army's new handgun, the Sig Sauer P320, is a polymer-framed, striker-fired design, but there's a lot more.
Sig Sauer P320 : The Army’s new handgun, the Sig Sauer P320, is a polymer-framed, striker-fired design, but there’s a lot more.
Tom McHale headshot low-res square
Tom McHale

USA –-( You’ve probably heard by now that the United States Army has selected a new handgun platform.

In case you haven’t, after years of searching, testing, and generating metric tons of paperwork, the United States Department of Shooting and Spending has determined a winner: the Sig Sauer P320 . ( )

The last time a big switch like this happened was back in 1985, the same year that Coca-Cola introduced that “New Coke” thing. Coincidence? I think not. Not only did the Army switch handgun platforms from the 1911 to the Beretta 92 / M9, they switched calibers from .45 ACP to 9mm. This time around, the caliber part is a little bit squishy as the finalist guns were all somewhat multi-caliber in nature.

So what’s the big deal about the Sig Sauer P320 handgun that enabled it to earn the prestigious $500+ million Army Modular Handgun System (MHS) contract for guns, parts, and services? Let’s take a closer look.

Sig Sauer P320 Handgun

First and foremost, the P320 does away with the double-action / single-action operation that’s been in use the past 22 years. That’s neither a benefit or a drawback, it just is. There are great reasons to choose a double-action / single-action. There are great reasons to choose a striker-fired design like the P320. They’re just different.

So, just to be clear, the P320 as a striker-fired gun has the same trigger pull sensation from first to last shot.

The one sitting on my desk as I write this has a 6.25-pound trigger weight each and every time. In theory, when your business is teaching hundred of thousands of people to shoot a handgun, that constant trigger press makes things easier. It’s heavy enough to minimize the risk of an inadvertent discharge but light enough to facilitate accurate shooting.

The other big visible difference from the Beretta M9 is that the Sig Sauer P320 is made of plastic, or at least the frame is. In fact, most of the MHS entries from Beretta, Smith & Wesson, and Glock were polymer-frame guns. Not only are they lighter, but they’re also cheaper and easier to manufacture and less finicky about environmental concerns like rust. Of course, the bang-bang stuff like barrels and slides are all steel, it’s just the support infrastructure that’s made of polymer. You’ll also notice a mil-spec rail up front and ambidextrous slide release levers.

Legally, this chassis is the Sig Sauer P320 Handgun. It's the serialized component, so everything else is just... parts.
Legally, this chassis is the Sig Sauer P320 Handgun. It’s the serialized component, so everything else is just… parts.

Those two things are the big visible differences, but what really drove the choice was the modular nature of the Sig Sauer P320. Unlike most pistols, the “gun” portion, at least in a legal sense, is a self-contained fire control system chassis. This central assembly contains the trigger, striker, ejector and other fire control gizmos and simply lifts out of the frame. The grip frame, barrel, recoil spring, and slide are just non-serialized parts.

Why is that a big deal? The “gun” has no caliber, length, height, or weight. All of that depends on the parts you use around the “gun.” For example, once you have the fire control chassis, you can use it to assemble a 9mm full size, .40 S&W compact, or perhaps a .357 Sig Sub Compact, or virtually any other combination of frame size, barrel length, and caliber.

With the Sig Sauer P320 design, all of these components are just parts, and can be mixed and matched to change size and caliber.
With the Sig Sauer P320 design, all of these components are just parts, and can be mixed and matched to change size and caliber.

Not having been on the Modular Handgun System selection committee, I can only guess, but I’d bet lunch that the idea of having interchangeable plastic frames had a lot of appeal for the Army folks. Some people have big hands while other Presidents, I mean people, have small hands. Sure, there are solutions on other pistol platforms that adjust grip size with insert grip panels attached by pins. But if you’re buying a billion guns that are going to get abused in the worst of conditions for a couple of decades, I would think that having whole frames with different grip sizes would be an appealing thing. No loose parts, no pins, and no grip panels to track and reconfigure. Plus, if one gets destroyed, you can just pull another whole frame out of the parts bin and swap it out.

I suspect there’s going to be a big administrative advantage to the modular idea too. When eleventy-billion HumVee loads of serialized items are purchased by a big bureaucratic behemoth like the U.S. Department of Endless Bidding Procedures, inventory management, and tracking becomes a really big deal. In theory, the modular system can make this a lot simpler as there is no “hard coded” association between a “gun” and it’s size, shape, or caliber. The serialized gun is the internal fire control chassis that works with any grip frame, barrel, and slide. It’s also not caliber specific (at least for 9mm, .40 S&W, and .357 Sig), so if the Army wants some of them to be configured in .40 S&W for a while, it’s no big deal.

All of the components required to reconfigure guns for different applications are just non-serialized parts. Armorers are going to be busy, but at least the configuring job is simple.

Presumably, one of the features the Army liked on the Sig Sauer P320 Handgun was the mil-spec rail.
Presumably, one of the features the Army liked on the Sig Sauer P320 Handgun was the mil-spec rail.

Shooting the Sig Sauer P320 Handgun

So those are the feature basics of the Sig Sauer P320 Handgun, but how does it shoot? I’ve been testing a full-size model chambered in .357 Sig for a while now, and I’ve been very pleasantly surprised by this gun. The trigger is excellent. The measured weight is 6.25 pounds, but the feel is where the P320 shines. This one has about 1/4-inch of effortless take-up, followed by 1/8-inch of constant pressure, followed by a crisp break. If you’re into riding the reset, that’s clearly audible and tactile after about 3/16-inch of forward release.

The real surprise of the P320 was its accuracy. I had three different Sig Sauer pistols, all chambered in .357 Sig, at the same time and tested them side by side using a handgun scope mounted with a UM Tactical Rail mount. I expected the venerable P226 and P229 pistols to seize the accuracy honors because they’re all metal and have storied reputations. However, just the opposite happened. Don’t get me wrong, the P226 didn’t disappoint – it easily generated 25-yard, five-shot groups under three inches almost every time with a broad variety of ammo. However, the P320 beat that handily, knocking out quite a few sub-two-inch groups. For example, the first three five-shot, 25-yard groups measured just 1.56, 1.92, and 1.61 inches using Sig Sauer’s V-Crown 125-grain .357 Sig loads. Other ammo shot equally well.

You get the idea. This gun will shoot.

The Army version, now known as the XM17, sports a cool color and a manual safety lever.
The Army version, now known as the XM17, sports a cool color and a manual safety lever.

If you look at the publicity photos of the Army MHS P320, you’ll notice an extra part that’s not on the standard commercial models, a manual safety lever. The commercial P320 has lots of internal safety mechanisms including a striker block (won’t fire unless the trigger is operated), disconnect safety (won’t fire out of battery), and a takedown safety (magazine must be removed, slide locked back, and no trigger press required to disassemble the gun.) However, the Army folks wanted an external manual safety, so Sig Sauer added one to the MHS XM17model. We can safely assume that the manual safety version will be an option for the commercial market at some point too.

So there you have it. Big news from the Army, they’re getting new pistols. Given the speed at which our Armed Forces supply chain operates, I suspect it’ll take a few centuries for Sig Sauer P320 pistols to arrive on the line, but it’s in progress, starting now. If you want one, I might suggest moving quickly as lots of folks are going to want “the Army’s pistol” and it would be surprising if future production capacity wasn’t strained.


Tom McHale is the author of the Insanely Practical Guides book series that guides new and experienced shooters alike in a fun, approachable, and practical way. His books are available in print and eBook format on Amazon. You can also find him on Google+, Facebook, Twitter and Pinterest.

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Jack Patrick

I agree withthe comments below. You lost me at the small hands crack. I don’t care how many books you’ve written, you’re a sore loser and a political idiot, Real people aren’t interested in watching you throw your rattle.


I was a young soldier in 1985 when it was announced the M1911 would be replaced by the M9. I had my grandfather’s Colt Government model he bought in 1930 from the PX in China where he was based at that time. Like my granddad, I thought it would be fashionable to own a civilian version of the issue pistol. The gun rags didn’t even talk about “wonder nine’s” at that point. I was stationed in Germany at the time; as soon as I had saved up the cash, I purchased a Beretta 92 FS-B at the PX just like… Read more »

Jack A Furbush

I disagree with your opinion of the 320. The 3 different calibers option were intended for the civilian and Lawenforcement market. They are giving the Glock and S&W M&P a good challenge. I have two 320 pistols and all 3 caliber options in a couple of configurations. I’ve fired just about every 9mm & 40 S&W round available with almost no hiccups. That includes U.S. and other types of NATO 9×19 rounds. No issues. I’m not sure where you get the lite strike thing from. The weapon goes bang every time I pull the trigger, how much more do you… Read more »


He may have small hands, and some other issues, but where would we be if Clinton was in office now? Where would the gun community be? What would our future look like under her? I’d rather not even know! You can take a few slaps at him if you wish, and i certainly dont think he is perfect in any way, but look at the alternative! yeah, i’m one that voted lesser of two evils and a lot of that had to do with 2A issues.


I thought the joke was funny. Lighten up guys. Had he bashed Obama there would have been jeers in the room. By the way extremely informative article.


How does a pistol that can shoot three different caliber rounds with three different configurations not become a logistical nightmare for the military? After reading the article it sounds like Murphy’s law was never considered. The troops on the ground that will carry the Sig P320 into combat aren’t all gifted with Einstein’s intellect. The words “keep it simple stupid” becomes relevant. I am a retired Marine MGYSGT E-9 and my MOS (military occupational specialty) was Supply and Logistics. The more complex you make something the more likely something will go wrong. Military personnel have to qualify periodically with their… Read more »

M2 Mike Golf

It sounds as though you know little about the M17/M18 or what was selected by the Army, or you didn’t read the story…or both. As far as your qualification of “supply and logistics” MOS, all I’ll say is this. I’m one of those lower intellect I think you referenced; I’m a retired US Army infantryman and a lowly SFC. Additionally, I was a master gunner for 18 of my 24 years in the infantry. Your elitist attitude about how dumb grunts not being able to use a firearm that’s been issued or be able to maintain or employ it is… Read more »

Jack A Furbush

Hey Master/Guns. I spent 22 years in the Corps myself. Regular grunts and support Marines would be issued the M17. MUSOC/RECON Marines are a couple of notches above. The modular features bennifits them and every other components of the spec war people in heavy use today. Recon Marines, SEALES/ Rangers/SOFDD all have their ideas on what they need for weapons and grear. This also eliminates the need to keep 17 different handguns and the spare parts to support them and the special training to support each systems. During GW1 the recoil spring in the 1911A1 I carried failed. No resplendent… Read more »

Michael Hetherington

I will never understand people who use practical non-political articles like a gun review to take cheap shots at a politician. People don’t come to this site to listen to political sniping. This is in the same category for me as having to listen to politics when I’m trying to watch sports. I understand that it is a small joke and I am really not offended by it. I would simply prefer that you keep that type of writing to sites such as slate or Huffington Post or some other feelings-based nonsense site. I’ll go about my day and really… Read more »


I strongly second that request. If we wanted the political opinions of the writer we’d ASK for same. We didn’t, and don’t.


Honestly, I think this was a mistake. Now, I’m not going to say , “oh they should’ve adopted the 1911 or a Glock!” But honestly there are better guns than the 320. Why wouldn’t a modified HK USP be considered? Literally has the lineage of the most most tested military pistol on the planet. It’s ultra reliable, very accurate, soft shooting, and has safety features the Army would get a chub over. Safety and decocker in one lever. The whole modularity feature of the Sig is dubious at best for the military. The only usefulness it provides is that it… Read more »

Jack A Furbush

I disagree with your opinion of the 320. The 3 different calibers option were intended for the civilian and Lawenforcement market. They are giving the Glock and S&W M&P a good challenge. I have two 320 pistols and all 3 caliber options in a couple of configurations. I’ve fired just about every 9mm & 40 S&W round available with almost no hiccups. That includes U.S. and other types of NATO 9×19 rounds. No issues. I’m not sure where you get the lite strike thing from. The weapon goes bang every time I pull the trigger, how much more do you… Read more »


I shoot a lot of different guns. Once you get accustomed to the grip angle and trigger, the 320 is a top shooter. I can’t see that great any more, and can still get hits on a 12 inch plate at 65 yards – and that is with the compact slide. I like big calibers too, but these days I would like lots of rounds handy without the weight. I put my smith 329 44 back in the drawer and carry a 320 compact and extra mag. Other than the chubby feel, my only gripe would be higher visibility front… Read more »

Dalton James

Ok article until you made the small hands comment so now I m thinking the article is fake news in respect on how good the gun is . Give me a 45 anytime especially in a double stack .

scott horn

Well written…. up until your small handed president comment…. that alone made this article suspect and removes credibility from your opinion. Its amazing to me that libturds just cant stick to a topic without adding political bullsh_t to it… well done. And im sure my comment wont be posted because it goes to “moderation” prior to posting, and liberal are all about censorship…

Quince Kreb

Thank you for the review of the Army’s new pistol, as it was very informative. I was waiting for review specs as I do like to keep up on things, even though I’ve been retired for 4 1/2 years now. I was first introduced to the 1911 .45 as my sidearm with the Arctic Light Infantry in 1988. I then went Aviation as a crew chief on UH 60 Black Hawks and they still had the .38 revolvers in 1990, but issued the Beretta 9mm for Desert Shield and Storm. Of course thelse pistols is what we carried on our… Read more »



L Hutson

I own the 320 there pieces of junk I traded it for an M&P


When I came to the picture of the serialized component – the “chassis” – my first thought was: Would it be practical for someone to produce an 80% finished version of the chassis in much the same way that 80% lowers for AR-pattern rifles are being produced? It would probably have to be steel rather than aluminum which would make it a bit harder to finish with typical home workshop tools, but still . . .


The military is not constrained with “just” using contact ammo, either FMJ or JHP… Special operators budgets and supply/support have access to what they need. As far as LEOs and civilians, today’s premium ammo, even for 9mm, are capable of defeating Class IIIa armor, cracking/penetrating cinder block walls, car bodies/glass, and others, i.e., are barrier blind, and far more capable than ammo originally intended for M1911A1 and M9… Modularity means easier, more rapid replacement/maintenance at field or depot levels. Duties of armorers will be greatly reduced, and troops/personnel will have more reliable, dependable weapons that will be much easier to… Read more »


Wow! The finish on that (top pic) gun is already pretty beat up. The FDE pistol looks like that finish might hold up better…maybe.

Ol' Vet

Don’t want to post my comment?

Now my email not valid??


Ol' Vet

Just wonderin’ about the knock-down power of that weapon. Germans always made great quality pistols but they were garbage compared with the M1911A1. Multi calibres? Why? Ammo for that thing would cost a fortune, and with soldiers not experienced in firing a pistol, where is the first round going and how hard will it to be to bust a concrete block in one of those middle-Eastern houses, which was a complaint from the field in Iwack when the boys needed to get to a sniper, or other hidden folks…but that was the same with the M16/M2 firing the pitiful .22… Read more »


Why would ammo in common calibers like 9mm Luger somehow cost a fortune for this pistol?

Also, “knock down power” in a pistol is basically a myth – but the P320 comes in 45 ACP if that’s your preference.


As a retired federal firearms instructor, federal law enforcement officer, and Vietnam vet, I disagree. Don’t forget that the guys with these and rifles will actually carry them full time along with ammo. Adding a few pounds of guns and more pounds with ammo is significant. Our modern troops now carry huge amounts of weight, and adding more for no ballistic difference is not wise.


I’ve been hearing this same old crummy argument since I was in the Army in 1987-1990. The .223 is NOT a .22. You’re either shoveling manure or don’t know what you’re talking about. This “knockdown power” crap has been around forever, and nobody who uses it has ever offered any evidence that it matters.

Bob M.

For any of you still not paying attention: We’re broke. Hey but at least the Army will be able to buy a fancy new pistol on credit, right?


I don’t think I have read an article that mentions the plate. I don’t think it was s requirement. That being said I don’t see it being a standard feature. It is a part that can get loose and come off. Uncovered it would also leave 2 holes on the slide exposed for debris to get into the inside if the gun. But yes it is pretty glaring and should have been mentioned.


If the picture is to be believed, the author fails to mention a big feature. That is, there appears to be a removable plate atop the slide which is removable to mount optical sights.

Jim Brannan

I can’t wait. It can be modified to be every gun you want at less than every gun you want. This is a dream come true, a year from now, maybe. I am so glad for the single minded Glock, 1911, Baretta only people, and the I’ll never buy a plastic gun people. That will make it that much faster for me to get my XM17 Sig and accessories.


No, it is not a solution looking for a problem. It was a problem that required a solution. The frame is modular as well. The M9 grip fit folks with med/large hands well, but not people with med/small hands. The grip sizes vary from large to small via their circumference. You will find the most popular size of P320 frame is small and medium. The modularity of the caliber has no bearing in this instance as the takedown lever will be locked into position and will not be user removable preventing the removal of the FCU. The P320 is lighter,… Read more »


The benefit of so-called modularity is a solution looking for a problem. So what you can change calibers? The US Army will issue their proven 9mm FMJ ball round to their soldiers. Not 45, not 357, not 40…standard issue 9mm rounds. Special Forces, Army Rangers, SEAL teams already use the pistol they want. Think they want to deal with a modular pistol? A new pistol? Not!!!
So maybe the Army didn’t like the very fine Beretta M9A3, or the S&W M&P, or the Glock 17. Maybe the whole trial turned on price….

Richard Heipp

I just won a new p320 in a drawing at Mega sports in Plainfield, IL about two weeks ago. It’s a compact 9mm and came with 2-15 round magazines and holster. The first 30 rounds I shot blew me away the grouping was so freaking tight. The fit feel and overall performance was second to none. I used the P320 to qualify for my ccl. The groups where so tight the instructor told me to spread um out. You couldn’t tell I fired ten shots. I like it so much I am going to buy one. I rave to everyone… Read more »


Can I get one with a 6″ target barrel? And a vertical muzzle break? And threads for a suppressor? And chromed metal parts to contrast with the polymer? That would be sweet.


Having shot, studied, and accumulated (not exactly collected) various pistols and revolvers for over 50 years, I can vouch for the quality of SIG Sauer pistols. I learned to shoot pistols in the Army, when my duty weapon was the 1911A1. I also learned the difference between its and it’s around the fourth grade. And like the author of the article, I also “revere” my pistol’s magazines — as per the paragraph under the last photo. (This kind of thing is why the liberals call us dumb rednecks. Can’t people proofread their writing?)

Sam Cohen

In case you’re wondering: After my post, Ammoland corrected the author’s typo from “magazine must be revered, slide locked back” to “magazine must be removed, slide locked back” — but they still left in “…association between a ‘gun’ and it’s size, shape, or caliber,” ignoring the misuse of I-T-apostrophe-S.” Sheesh.

Ross Taylor

“Some people have big hands while other Presidents, I mean people, have small hands.” Really??? Odd that a writer for a gun blog would snipe at a President who will defend the 2nd amendment while the alternative wanted an Australian style gun ban or worse. Your credibility for me – zero.


Aww did your poor little stereotype of how a gun owner votes get smashed.

HMLA-167 Warrior

, wow, lighten up a little. It was a joke and not even one that he made up, or anyone including trump himslef took seriously. Sheesh.

, Do you seriously think that because the author rehashed a joke in his article he must have voted a certain way and expectations must have been dashed? Really? Lol


I second that

George Van Riper

Three different US calibers on the battlefield is stupid. AMMO interchangeability with NATO and other allies which used to be a good thing has gone out the window. This is the worst kind of social engineering to accommodate people with small hands and recoil aversion. No thanks. If you are going to abandon the 9 MM than give me a 1911 in 45 ACP with a large capacity magazine. A Vietnam Helicopter Pilot who “acquired” a Browning HiPower with two magazines in lieu of an S&W 38 SPC 4″ revolver with five rounds and no speed loader!


The M9 was made in the USA. The P320 was designed here and will be made here. It is a stipulation of the contract that they be built here. S&W did have an entry I believe but did not make it through. The money and jobs never left.


So, we went from Beretta (Italian) to Sig Sauer (German), NOBODY in THIS country makes a military grade pistol ? Colt, S&W. Ruger, etc ????
Keeping the money and labor here would be a HUGE plus.


I think these will be produced at their New Hampshire facility.


Yes. These will be entirely NH (live free or die – just enacted Constitutional carry) USA manufactured. At least, that’s what they have said officially.


From what I see, my .40 S&W model was made in Exeter NH. It’s molded into the frame.


My manufacturing facility is producing two pins for this pistol, here in Ct. We ship directly to New Hampshire where they are producing these pistols.
Sole producer is NH facility in the good ole USA

Craig Olmsted

Used my overpaid taxes rebate on a ..45 P320. I’m pleased with it shoots, I’m looking forward to them coming out with the carry size module and slide. I’m unsure why Sig only makes 10 rd mags for the .45


Man! I’ve wanted one of these for some time now before the Army contract. Unfortunately, they’re not available in California unless your exempt li!e am LEO. There’s at least a 100% markup on P320s on private party sales.

Charles Valenzuela

I am under the impression that this is to be a double-action only (DAO) pistol. Like the SIGs issued to air marshals.


It’s a SAO striker-fired pistol like a Glock, M&P or XD but with a WAY better trigger (feels like a P226 in single-action in “locked & cocked” mode but with a slightly heavier pull… at least compared to the polished SRT on my other SIG’s) and is truly modular not only in caliber but in “grip-frame” size and shape (3 sizes with 3 grip profiles each). I have one of the full-size Gen 1 P320’s in 9mm and it’s the absolute BEST striker-fired pistol I have ever owned or used (this includes highly modded Glocks, M&P & XD and a… Read more »

Webfoot Logger

It’s striker-fired, and neither double-action nor single-action in that the trigger pull is exactly the same every shot, and it does not require cocking.


MY goodness you mean the government actually did something that seems RIGHT for a change. What are we going to do???????????? It’s hard to understand that the government could think that way and make it work……. Good thing it’s about time the modular weapon concept was looked at for the Military. Remember this though – it has taken this long in firearms development to be able to have this kind of system that works well enough for it to be used by the military and that is no small achievement. Sig Sauer did it and that is good.


Ugh. Plastic guns. Nope.

Mr. Oli

It’s not a plastic gun. Did you not read the article?


Yeah, you mean the part where it says the frame is made out of plastic??


Calling a polymer frame “plastic” is like calling an aluminum frame “tin foil”.

Tom S.

No it’s like calling it metal.

Ronald P. Farinetti

Shoot and then See what You have to say, It really is a Great Gun….


Yea, you all said that about the Kimber Solo. Shoot about 50 rounds before it name, then clear it so it will jam again.


Try this: take a piece of quality aluminum and a similar piece of quality plastic. Wack them both with a reasoanble hammer, and see which one is still useable. Hint: It will not be the metal one.


The manual safety models are already commercially available but only in compact form. Currently they are hard to find and the first few released were part of a Mass LEO contract. I have adapted my manual safety compact to a subcompact and full size frame.


Won’t publish my comment huh? Well, I guess that figures. Snowflakes that cannot take an opinion that differs from theirs MUST be silenced huh?


The 320 is the only pistol that Failed the testing evaluation of the SanAntonio police dept.

When you are shooting your 9mm 320 next, place forward pressure on the mag base pad, the pistol will malfunction every time. Bore axis is also way to high for fast shooting, you won’t see this in competition much…but then the folksvthet are going to be issued too won’t have that much training on a handgun anyway.


I tried that with mine. It had no problems. I also threw my P320 on the floor numerous times, no discharges. For what’s worth, I was infantry for 24 years, ’84 to ’08. I’ve had some practical use with a G19 and own one. I think the SIG is great, I can’t really say better, or worse. On that subject, for years LEOs have been complaining about Glocks “going off”. I’ve yet to see that one either. Seems to me some PDs have a lot of problems with negligent discharges and like to blame the weapon. The only gun I… Read more »


Good review… and Jesus ya super sensitive snowflake nancies… the guy isn’t allowed to tell a hands joke?


Great article until the dumb hands/ president reference. The author is a giant lib douche.


Did not care for the passive aggressive Presidential joke in this article. Go back to the Huff Post if you want to write that crap in. Why are you reviewing guns?

Military combat forward air support.usaf.

Not our president commandant

Jack A Furbush

Spot on. You seem to over look a simple fact. The reason you can still have that evil assult weapon that only belongs on the battlefield is because Trump has made it plain that he refuses to sign any gun bans into law. Think about that before you bad month the President again.