Mcx Spear 6 8X51

About this product

The Sig Sauer MCX-Spear is the civilian version of the rifle the U.S. Army adopted as the XM7, built around the 6.8x51mm cartridge (marketed commercially as .277 Fury) for more energy downrange than 5.56 NATO. This listing is priced at $4,999, which lines up with the rifle's original civilian launch MSRP, and because it is a firearm it ships to a licensed FFL dealer for pickup — never to a home address.

What is the MCX-Spear 6.8x51 good for?

Buyers searching for a 6.8 mcx spear for sale are usually looking for a hard-hitting, magazine-fed semi-auto rifle for long-range shooting, hunting larger game, or a modern military-pattern rifle built to handle a high-pressure cartridge. The 6.8x51/.277 Fury round was developed to push more velocity and energy than 5.56 or even standard 7.62x51 loads out of a similar-length barrel, which is why the platform has drawn attention from hunters and long-range shooters, not just military-pattern rifle collectors.

What comes with the MCX-Spear?

The MCX-Spear runs a short-stroke gas piston system in Sig's modular MCX chassis, feeds from 20-round SR-25-pattern magazines, and is available with either a 13-inch or 16-inch barrel depending on configuration. Every barrel ships with a 5/8x24 threaded muzzle and a QD-compatible flash hider already installed, and the platform is designed so the upper can later be converted between 6.8x51, 7.62x51, and 6.5 Creedmoor. Out of a 16-inch barrel, Sig's factory ammunition is rated to break 3,000 fps with a 113-grain bullet, which is serious performance for a semi-auto platform.

Is the MCX-Spear California compliant?

This is the question we get asked the most on this listing, and the honest answer is that it depends on configuration and current law, not on us telling you what you want to hear. California's assault weapons statute restricts semi-automatic centerfire rifles with a detachable magazine when they also have certain features — a pistol grip, adjustable or collapsible stock, flash hider, and so on — and the MCX-Spear as sold nationally includes several of those features. We are not going to claim this rifle is California-legal as configured; Sig Sauer does not market this specific variant as CA-compliant, and you should not assume it is. If you are in California, talk to your FFL before you order about what configuration would actually be lawful for you to take possession of, and confirm current state law, which does change.

How does the MCX-Spear compare to a standard AR-15?

Beyond the caliber, the MCX-Spear's short-stroke gas piston system is a meaningful departure from the direct-impingement operation most AR-15s use — a piston keeps fouling and heat out of the receiver and bolt carrier, which tends to mean a cleaner-running gun between maintenance cycles, at the cost of some added weight and a bit more complexity to fully disassemble. Sig also builds the MCX-Spear with a full-length Picatinny top rail and M-LOK slots around the handguard, so mounting optics, lights, and other accessories does not require any separate rail sections. The price reflects all of that: premium materials, military-informed engineering, and a cartridge purpose-built to outperform 5.56 at range.

Checkout is handled through our secure checkout. Once payment and your background check clear, we will coordinate the transfer to the FFL you choose. If the MCX-Spear passes your state's compliance check, it is one of the most capable magazine-fed semi-auto rifles on the market right now.