GunsAmerica

Quick Look

The Sig Sauer M18 is the compact variant of the U.S. military's Modular Handgun System adopted in 2017. Designed for adaptability, it offers a balance of size, modularity, and proven reliability. The M18 remains popular among service members and civilian buyers seeking duty-grade performance in a compact frame.

Why It's a Top Choice

Official sidearm of the U.S. Army, Navy, Air Force, and Marines
Modular fire control unit allows grip and slide swapping
Factory optics-ready slide with removable rear sight plate
Enhanced corrosion resistance with coyote PVD finish
Dual-stack 17- and 21-round magazines for extended capacity

Key Variants

Sig Sauer M18 Commemorative

A civilian-legal replica matching the exact specs of the military-issue M18, ideal for collectors and enthusiasts.

Sig Sauer P320-M18

Same modular chassis and performance as the issued M18, built for duty, defense, or carry use.

Competitor Comparison

Feature	Sig Sauer M18	Glock 19	Smith & Wesson M&P9 M2.0
MSRP	$699	$539	$599
Capacity	17+1 / 21+1	15+1	17+1
Weight (unloaded)	28.1 oz	23.6 oz	24.7 oz
Optics-ready	Yes	No (MOS models only)	Yes
Trigger type	Striker, modular FCU	Striker	Striker
Pro	Military-issued, modular platform	Proven reliability and simplicity	Excellent ergonomics and texture
Con	Heavier, higher MSRP	No native optics cut	Fewer aftermarket options

Best Use Cases

Concealed carry
Law enforcement duty carry
Military-style training
Home defense
Firearm collection of issued weapons

FAQs

What is the difference between the M18 and P320?

The M18 is a specific P320 variant adopted by the U.S. military, with a manual safety and coyote finish.

Can I mount a red dot on the Sig Sauer M18?

Yes; the M18 has a factory optics-ready slide compatible with DeltaPoint Pro and ROMEO red dots.

How does the modular chassis work in the M18?

The fire control unit is serialized and can be dropped into different grip modules and slides.

SIG SAUER M18 for Sale