Sig Sauer P320 Pistols
The P320 is a striker-fired pistol built around a removable fire control unit. That unit is the serialized part. The grip, slide and barrel swap, so one P320 can be a full size gun today and a compact tomorrow. We stock the Full Size and Compact, the military M17 and M18, the X-Series, the 10mm XTEN and Sig's competition models.A modular striker-fired pistol: swap the grip and slide to change its size. Every model we stock, side by side.
Prices from $481.25 to $2,199.99, as of Nov 13, 2026.
Pick your P320
Every P320 line we list, with the count in stock and the lowest price for each.
Full Size4.7 in barrel · 17 rd
CarryFull grip · 3.9 in · 17 rd
CompactShorter grip · 3.9 in · 15 rd
XFullX grip · 4.7 in · 17 rd
XCarryX grip · 3.9 in · 17 rd
XCompactX grip · 3.6 in · 15 rd
M17Army full size · 4.7 in · 17/21 rd
M18Army carry size · 3.9 in · 17/21 rd
XTEN 10mm10mm · 5.0 in · 15 rd
X-Five LegionCompetition · 5.0 in · 17/21 rd
MAX / SXGCompetition · 5.0 in · 21 rd
Spectre CompComp · 4.6 in · 21 rd
AXGMetal X grip · 3.9 in · 17/21 rd
Romeo-X / RXPRed dot included · 3.6 to 4.7 in · 15/17 rd
FluxChassis with brace · 5.5 or 3.9 in · 30 rd96P320 pistols in stockShop all All P320 pistols
96 in stock. Sold out listings stay up, after the ones you can buy today.
Compare P320 models
The most listed size for each model in stock. 10 round versions of most models are listed for states with magazine limits.
As of Nov 13, 2026
Compare P320 models
The most listed size for each model in stock. 10 round versions of most models are listed for states with magazine limits.
| Model | Size / grip | Barrel | Standard mag | Calibers | In stock | From | Shop |
|---|---|---|---|---|---|---|---|
| Full Size | Full grip | 4.7 in | 17 | 9mm | 6 | $496.36 | Shop |
| Carry | Full grip, shorter slide | 3.9 in | 17 | 9mm | 1 | $643.25 | Shop |
| Compact | Compact grip | 3.9 in | 15 | 9mm, 45 ACP | 5 | $481.25 | Shop |
| XFull | X grip, full | 4.7 in | 17 | 9mm | 6 | $729.99 | Shop |
| XCarry | X grip, carry | 3.9 in | 17 | 9mm | 3 | $729.99 | Shop |
| XCompact | X grip, compact | 3.6 in | 15 | 9mm | 7 | $729.99 | Shop |
| M17 | Full size, coyote or black | 4.7 in | 17 or 21 | 9mm | 9 | $684.60 | Shop |
| M18 | Carry size, coyote | 3.9 in | 17 or 21 | 9mm | 8 | $699.99 | Shop |
| XTEN 10mm | X grip, full | 5.0 in (comp 3.8 in) | 15 | 10mm | 11 | $799.99 | Shop |
| X-Five Legion | Full, TXG grip | 5.0 in | 17 or 21 | 9mm | 4 | $1,029.99 | Shop |
| MAX / SXG | Full, competition | 5.0 in (comp 3.9 in) | 21 | 9mm | 10 | $899.99 | Shop |
| Spectre Comp | X grip, comp slide | 4.6 in | 21 | 9mm | 3 | $1,429.99 | Shop |
| AXG | Alloy X grip | 3.9 in | 17 or 21 | 9mm | 6 | $892.30 | Shop |
| Romeo-X / RXP | Sold with a Sig red dot | 3.6 to 4.7 in | 15 or 17 | 9mm, 40 S&W | 7 | $895.32 | Shop |
| Flux | Chassis with brace | 5.5 or 3.9 in | 30 | 9mm | 2 | $1,399.99 | Shop |
Source: barrel, magazine and caliber are taken from our in-stock listings for each model. 8 more P320 listings are in the full grid.
Built for your P320
Magazines, holsters and parts that fit the P320, from Sig and other makers. Parts ship to your door where your state allows.
What makes the P320 modular
Most pistols have one serialized frame, so the gun you buy is the gun you keep. On the P320 the serialized part is the fire control unit (FCU), a stainless steel chassis that holds the trigger group and sits inside a polymer or metal grip module. Legally the FCU is the gun. Grip modules, slides and barrels are parts, so they can ship to your door where your state allows. That means one P320 can change size, grip texture or color later. See P320 grip modules and P320 slides.
P320 sizes explained
Sig built the P320 in four main sizes. The Full Size has a 4.7 inch barrel and a 17 round magazine in 9mm. The Carry pairs the same full length grip with a shorter 3.9 inch barrel, which keeps the 17 rounds but trims the front of the gun. The Compact uses that 3.9 inch slide with a shorter grip and a 15 round magazine. The XCompact goes shorter again with a 3.6 inch barrel and 15 rounds. If you are not sure, the Carry is a good middle choice: full grip for shooting, shorter slide for holstering.
Sig M17 and M18
In 2017 the U.S. Army picked the P320 as its Modular Handgun System. The full size version became the M17 and the carry size version became the M18. The commercial versions we sell are 9mm, most in coyote tan, with a 4.7 inch barrel on the M17 and a 3.9 inch barrel on the M18. Our listings show 17 and 21 round versions of both, plus 10 round versions for states with magazine limits. We have 9 M17 and 8 M18 listings in stock.
The X-Series
The X-Series uses Sig's X grip module, which has a higher undercut behind the trigger guard and a longer beavertail, so your hand sits higher on the gun. It comes in XFull (4.7 inch), XCarry (3.9 inch) and XCompact (3.6 inch), and most X models have an optic-cut slide. The X-Five Legion is the heavy competition version with a 5 inch bull barrel.
XTEN and 10mm
The XTEN is the P320 in 10mm. It has a 5 inch bull barrel, a flat trigger, an optic-ready slide and a 15 round magazine. The XTEN Comp is the shorter version. Pair it with 10mm ammo built for your use, since 10mm loads run from light range rounds to full power hunting loads.
Calibers
Most P320s are 9mm. Sig has also made it in .40 S&W, .357 SIG, .45 ACP and, with the XTEN, 10mm. Right now we stock 82 in 9mm, 11 in 10mm, 2 in 45 ACP and 1 in 40 S&W. Shop 9mm ammo.
P320 vs P365 vs Glock 19
All three are striker-fired 9mm pistols. The difference is size and what you want the gun to do.
- 3.9 in barrel
- 15 round magazine
- Swap grip and slide to change size
- 3.1 in barrel (base model)
- 10 round magazine
- Built for all-day carry
- 4.02 in barrel
- 15 round magazine
- Wide choice of holsters and parts
Pick the P365 if hiding the gun is the top priority: it is much smaller and lighter. Pick the P320 if you want a pistol that is easier to shoot well, holds more, and can change size later. The Glock 19 sits close to the P320 Compact in size and capacity; the P320 adds the swappable grip. Many owners end up with more than one. Compare at Sig P365 and Glock 19.
Buying a handgun online
Magazines, holsters and parts ship to your door where your state allows. Check state restrictions before you order, and read how buying a gun online works. Firearms can go on layaway, and financing shows at checkout when the order qualifies.
More Sig Sauer series
Sig P320 FAQ
What sizes does the Sig P320 come in?
Full Size (4.7 in barrel), Carry (3.9 in barrel with the full-length grip), Compact (3.9 in barrel with a shorter grip) and XCompact (3.6 in barrel). Sig also made a Subcompact that has since been dropped. Because the grip module swaps, many owners change sizes later without buying a new gun.
What is the difference between the M17 and M18?
Both are versions of the P320 the U.S. Army adopted in 2017. The M17 is the full size gun with a 4.7 in barrel. The M18 is the carry size with a 3.9 in barrel. Both are 9mm, and the versions we list hold 17 rounds, with 21 round versions also available.
What is the difference between the P320 Compact and the P320 Carry?
They share the same 3.9 in barrel and slide. The Carry has the longer full size grip and holds 17 rounds; the Compact has a shorter grip and holds 15. The Compact hides a little better; the Carry gives you a full grip and two more rounds.
Should I get a P320 or a P365?
Get a P365 if hiding the gun is the top priority: it is much smaller and lighter. Get a P320 if you want a pistol that is easier to shoot well and holds more, and you can carry a bigger gun or mostly want it for the house and the range.
Is the P320 optic ready?
Most current models are. The X-Series, M17 and M18, XTEN and X-Five have an optic-cut slide, and the P320 Pro Full Size and Pro Carry we stock are listed as optic ready. Some older models are not. Each listing says whether the slide is optic ready.
What is the serialized part of a P320?
The fire control unit (FCU), the stainless steel chassis that holds the trigger group inside the grip module. Legally that is the gun. Grip modules, slides and barrels are parts.
Do you carry 10 round P320 models?
Yes. Many P320s we list come in 10 round versions, and some M17 and M18 listings are marked Massachusetts compliant. Check our state restrictions page before ordering.
Will any P320 magazine work in my P320?
P320 magazines are made for a given caliber and grip size. A full size 9mm magazine fits full size and carry grips and will stick out of a compact grip. A compact magazine fits a full size grip but will not fill it. Check the fitment line on each listing, or shop P320 magazines.
What calibers is the P320 made in?
Mostly 9mm. Sig has also made it in .40 S&W, .357 SIG, .45 ACP and, with the XTEN, 10mm. Right now we stock 9mm, 10mm, 45 ACP and 40 S&W models.