The SIG Sauer MCX Spear is a gas piston semi-automatic rifle in 7.62x51 NATO. The 13-inch barrel, 1:10 twist rate, and six-position telescoping folding stock combine in a Coyote Tan package weighing 8.6 lbs with a 35-inch overall length. 
 

Key Specifications 

• Make: SIG Sauer 
• Model: MCX Spear 
• Caliber: 7.62x51 NATO 
• Barrel Length: 13 inches 
• Overall Length: 35 inches 
• Action Type: Semi-Automatic 
• Twist Rate: 1:10 
• Cartridge Capacity: 20 rounds (detachable magazine included) 
• Item Weight: 8.6 lbs 
• Stock Material: Polymer with a collapsible design (6-position telescoping folding) 
• Finish Color: Coyote Tan 
   

Detailed Features 

 
The gas piston system keeps fouling out of the action compared to direct impingement designs, which matters for reliability when running suppressed or going extended periods between cleanings. The 1:10 twist rate stabilizes heavier 7.62 NATO projectiles well. 
 
At 13 inches the barrel trades some muzzle velocity for compactness. The six-position telescoping folding stock can collapse the overall length for storage or vehicle carry. The adjustable length of pull fits a range of shooters. The polymer stock keeps weight reasonable for a 7.62 platform.

The MCX Spear Coyote gets consistent praise for build quality and the platform's versatility. Owners appreciate how well the gas piston system handles various loads, and the compact configuration gets positive marks from those who want a 7.62 rifle that doesn't feel unwieldy.

Weight comes up regularly — at 8.6 lbs unloaded, it's on the heavier side for the class, and some shooters compare it unfavorably to lighter competing options. Price is the other consistent thread; the MCX Spear runs above most AR-10-style competitors, which divides buyers between those who consider the quality worth the cost and those who find it hard to justify against alternatives. Aftermarket accessory support, while growing, is still narrower than for standard AR-pattern rifles.