Sig Sauer MCX CO2 rifle 4.5 mm pellets

The SIG AIR range brings the ergonomics and robustness of SIG® firearms to air rifles, offering performance and ergonomics designed for recreational shooting and real-life scenarios. Reliability and finish are paramount.

The SIG AIR MCX Gen II is a CO₂ -powered semi-automatic rifle in .177 (4.5 mm) caliber, equipped with a 30-round magazine, a 46 cm rifled barrel, and an M-LOK handguard for accessories.

• Action: Semi-automatic (CO₂)
• Caliber: .177 (4.5 mm)
• Magazine capacity: 30 pellets
• Barrel: Rifled, 46 cm (18")
• Propulsion: 88g CO₂ cartridge (housed in the stock)
• Sights: Adjustable folding components (rear sight/front sight)
• Rails: M1913 Picatinny + M-LOK handguard
• Weight: ~3.27 kg
• Length: 883 mm
• Comes with a 30-round magazine and sight adjustment tool

Designed for recreational shooting and training

The MCX Gen II retains the modular design of the original model while offering a configuration optimized for the .177 caliber. Its 30-round capacity allows for rapid bursts, ideal for gong shooting, practice sessions, or demonstrations.

CO₂ propulsion & performance

Powered by an 88g CO₂ cartridge, the rifle delivers a claimed velocity of up to 545 fps , depending on the pellet weight and type. Energy and velocity vary depending on the projectile used and the ambient temperature.

Charger, speed and ergonomics

The 30-round magazine ensures a sustained rate of fire in semi-automatic mode. The M-LOK handguard, Picatinny rail, and partially metal receiver allow the rifle to be equipped with optics, lights, and a bipod while maintaining a typical MCX grip: reduced-angle handle, adjustable stock, and contoured butt plate.

Rifled barrel and precision

The 46 cm (18") rifled steel barrel offers good length to stabilize .177 pellets and improve accuracy, especially with projectiles in the recommended range (≈ 5.0–8.5 grains).

Security, pairing and maintenance

Equipped with an ambidextrous safety selector and folding sights, the rifle is designed for versatile and safe use. CO₂ cartridge operation simplifies maintenance—simply change the cartridge and wipe the barrel regularly after use.

Recommended use

Designed for target shooting , training and leisure, this rifle will appeal to users looking for a high-performance, modular and ready-to-use semi-automatic replica.

FAQ

• What type of shot should I use? .177 (4.5 mm) shot, 5.0–8.5 gr, is suitable for a good compromise between speed and accuracy.
• Which CO₂ cartridge is needed? 88g cartridge housed in the detachable stock.
• Can optics be mounted? Yes, M1913 Picatinny rail and M-LOK handguard compatible with optics and accessories.