Sig Sauer Cal-X Kit P320-M18 9mm Carry Coyote 17/21Rd
$454.50
The Sig Sauer Cal-X Kit P320-M18 9mm is a complete conversion system that transforms your manual safety P320 into the civilian version of the U.S. Marine Corps' trusted M18 platform. Built on the same reliability and precision that earned the M18 adoption across all U.S. military branches, this kit gives you a combat-proven carry pistol with modern optics capability. Whether you're building a duty-ready 9mm or upgrading an existing P320, this coyote-tan package delivers everything needed to go from box to range in one shot.
The kit pairs a full-size 3.9-inch slide with a carry-length grip module, both finished in durable coyote-tan PVD coating that resists wear and corrosion. The slide is cut for the SIG-LOC MHS footprint, making it compatible with the ROMEO-M17 reflex sight—bringing modern optics to a time-tested platform without custom smithing. You get SIGLITE front night sights and a removable night sight rear plate, so you're set for low-light scenarios right out of the box.
The kit includes three steel magazines (one 17-rounder and two 21-rounders) with aluminum bodies, giving you flexibility for carry or competition. The 3.9-inch barrel and recoil spring assembly are included, so there's no hunting for parts. The M1913 accessory rail accepts lights and lasers, and the manual safety lever provides an extra layer of control for carry or training. This is the civilian M18—the same platform trusted by Marines, now available to put in your hands.
Key Features
- Complete Cal-X conversion kit—slide, grip module, barrel, recoil assembly, and magazines all included
- SIG-LOC MHS optics-ready slide for ROMEO-M17 and compatible reflex sights (optic not included)
- SIGLITE front night sight with removable rear night sight plate for low-light shooting
- Coyote-tan PVD coating on slide and grip for corrosion resistance and durability
- Three steel magazines: one 17-round and two 21-round capacity
- M1913 accessory rail for mounting lights, lasers, and other tactical gear
- 3.9-inch barrel on carry-size frame—compact enough for daily carry, substantial enough for duty
- Manual safety lever for positive control and safe handling
Specifications
| Model | P320 M18 |
| Caliber | 9mm Luger |
| Barrel Length | 3.9 inches (99.06 mm) |
| Slide Material | Stainless steel, coyote-tan PVD coating |
| Grip Material | Standard polymer, coyote-tan |
| Grip Size | Carry-length |
| Sights | SIGLITE front night sight; removable night sight rear plate |
| Manual Safety | Yes |
| Accessory Rail | M1913 |
| Optics Ready | Yes (SIG-LOC MHS footprint) |
| Magazines Included | (1) 17-round, (2) 21-round steel magazines with aluminum bodies |
| Recoil Assembly | Included |
| Threaded Barrel | No |
Frequently Asked Questions
Can I mount a red dot sight on this kit?
Yes. The slide is cut for the SIG-LOC MHS footprint and is compatible with the ROMEO-M17 reflex sight and other optics that use the same mounting standard. The optic is not included with the kit.
What do I get in the box?
The kit includes the full-size 3.9-inch coyote-tan slide, the carry-length coyote-tan grip module, the 3.9-inch barrel and recoil spring assembly, and three steel magazines (one 17-round and two 21-round). You'll also get the SIGLITE night sights and the removable rear night sight plate.
Will this kit work with my existing P320 frame?
This is a Cal-X conversion kit designed to upgrade a manual safety P320. The kit includes a new grip module, so compatibility depends on your existing frame configuration. Consult Sig Sauer or contact us if you're unsure about your specific P320 model.
Is the barrel threaded for a suppressor?
No. The 3.9-inch barrel included in this kit is not threaded.
