Sig Sauer MCX Spear Pistol 7.62×51 13in 20rd Coyote
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Expert review
About this product
The Sig Sauer MCX Spear Pistol is a modular, short-barreled AR-platform pistol chambered in 7.62×51 NATO, designed to deliver full-power rifle ballistics in a highly adaptable 13-inch package from Ironclad Armory. It integrates SIG's next-generation controls and a fully ambidextrous layout with a suppressor-ready gas system, bridging the gap between a traditional battle rifle and a modern personal defense weapon. This configuration exists in a specific legal category as a pistol, which carries distinct regulatory implications for transportation and modification that every prospective owner must understand before purchase.
What is the Sig Sauer MCX Spear Pistol used for?
The MCX Spear pistol is engineered for roles demanding terminal ballistics and modularity in a compact form, primarily serving as a vehicle or property defense platform and a suppressed hunting rig for medium game under 200 yards. Its 13-inch barrel and two-position adjustable gas block allow it to run reliably with a suppressor, making it exceptionally quiet for a .308 Winchester platform, while the M-LOK handguard accepts lights, lasers, and grips for low-light scenarios. This is not a plinking gun; it is a purpose-built tool for shooters who need the authority of 7.62×51 in a package shorter than a standard rifle, like the Stevens 334 rifle in .308 Win.
How does the MCX Spear Pistol compare to an AR-10 pistol?
The MCX Spear pistol is superior in suppression readiness and controls ergonomics to a conventional direct-impingement AR-10 pistol, but it commands a significant price premium. Its proprietary short-stroke piston system and self-regulating gas valve drastically reduce gas blowback to the shooter when suppressed—a common complaint with DI guns—and its dual, fully ambidextrous charging handles offer immediate clearing options. However, at $4,070.99, it costs approximately $2,500 more than a baseline, quality-built AR-10 pistol from Aero Precision or PSA, investing that difference into its military-proven operating system and superior out-of-the-box suppressor compatibility.
What does it weigh and what are the dimensions?
Unloaded with no optic or accessories, the MCX Spear pistol weighs 7.8 pounds (3,540 grams) and measures 27.5 inches in overall length from the end of the buffer tube to the muzzle threads. The 13-inch cold hammer-forged barrel has a 1:10 twist rate, optimized for stabilizing heavier 7.62×51 projectiles like the 175-grain SMK, and the handguard provides 10.5 inches of continuous M-LOK attachment space at the 3, 6, and 9 o'clock positions. These dimensions make it 4.5 inches shorter than a rifle with a 16-inch barrel but result in a velocity loss of approximately 200-250 feet per second compared to that longer barrel.
Who is this NOT for?
This pistol is not for budget-conscious shooters, first-time firearm owners, or anyone unfamiliar with the National Firearms Act (NFA) regulations governing pistols and Short-Barreled Rifles (SBRs). The $4,070.99 price point is a serious investment, and the cost of .308 Winchester ammunition—around $1.20 per round for quality brass-cased fodder—makes sustained practice expensive. Furthermore, attaching a vertical foregrip to this pistol without first filing a Form 1 to create a registered SBR is a federal felony, a regulatory trap that inexperienced owners often stumble into unintentionally.
What's in the box?
The pistol ships with one 20-round steel magazine, a SLX/SLH QD flash hider installed on the 5/8-24 tpi muzzle threads, a user manual, and a cable lock. Notably, it does not include any iron sights, an optic, a sling, or a case, which represents an additional $500-$2,000 in necessary ancillary purchases to make the platform field-ready. This bare-bones approach is common for high-end firearms but contrasts with more complete packages like some Stevens shotguns that often include basic choke tubes.
Is the MCX Spear Pistol worth it at $4070.99?
Yes, but only for a specific user: someone who requires the absolute latest in suppressed, large-format pistol technology and has the budget for both the firearm and the requisite Tax Stamp for an SBR conversion. You are paying for SIG's military-contract R&D, a bomb-proof piston system that runs clean, and unmatched ambidextrous controls out of the box. If your use case is generic range shooting or hunting from a static blind with an unsuppressed firearm, a traditional bolt-action .308 rifle for under $500 will be more accurate and cost-effective.
Specs at a glance
Pros & cons
What works
- Two-position adjustable gas block – enables reliable suppressed/unsuppressed use in 10 seconds with a tool.
- Fully ambidextrous controls – including dual charging handles and bolt catch for left or right-handed operation.
- Suppressor-optimized piston system – reduces gas blowback by an estimated 70% compared to direct impingement AR-10s.
- 13-inch cold hammer-forged barrel – provides a 1:10 twist rate for stabilizing bullets up to 175 grains.
Trade-offs
- No sights included – requires immediate additional investment of $100-$800 for backup irons or an optic.
- Proprietary parts ecosystem – limits aftermarket upgrades and increases replacement part cost by ~40% vs. AR-10 standards.
- Heavy for a pistol – at 7.8 lbs unloaded, it is 2.3 lbs heavier than a typical 5.56 AR pistol.
- High ammunition cost – practice with quality .308 Win brass averages $1.20/round, or $24 to fill the 20-rd mag once.
Key attributes
| upc | 798681681372 |
| manufacturer | SIG SAUER |
| manufacturer part number | PSPEAR-762-13B |
| action | Semi-Auto |
| atf type | MODERN SPORTING RIFLE |
| barrel finish | Black |
| barrel length | 13'' |
| caliber/gauge | .308 / 7.62 NATO |
| capacity | 20+1-Round |
| color | Coyote |
| length | 24.5'' |
| magazine included | 1 x 20-Round |
| model | MCX Spear |
| number of magazines | 1 20 rd. |
| package height | 4.2 |
| package width | 11.4 |
| product type | AR |
| safety | Thumb |
| shipping weight | 10.4 |
| sights | No Sights / Optics Ready |
| state restriction (ca) | NO DIRECT SHIP TO CALIFORNIA |
| state restriction (ri) | NO DIRECT SHIP TO RHODE ISLAND |
| state restriction (wa) | NO DIRECT SHIP TO WASHINGTON |
| thread pattern | 5/8"-24 tpi |
Frequently asked questions
- Is it compatible with standard AR-10 parts?
- No, the MCX Spear uses a proprietary upper/lower receiver pairing, handguard, and bolt carrier group that are not interchangeable with standard DPMS or Armalite pattern AR-10 components. The only common parts are the pistol grip (MIL-SPEC) and some M-LOK accessories; magazines are specific SIG SR-25 pattern.
- Does this work with a Dead Air Sandman-S suppressor?
- Yes, directly. The factory-installed SLX/SLH QD flash hider is a standard suppressor mount compatible with SIG's SLH and SLX series cans. For a Dead Air Sandman-S, you would need to attach the appropriate KeyMo muzzle device (like a Dead Air KeyMo Flash Hider, part #DA102) to the 5/8-24 threads, which takes about 15 minutes with a vise and armorers wrench.
- Can the brace be replaced with a stock?
- Yes, but doing so legally requires prior approval from the ATF via a Form 1, creating a registered Short-Barreled Rifle (SBR), a process that currently takes about 30-45 days for e-filed applications and includes a $200 tax. The buffer tube is a standard diameter, accepting any MIL-SPEC carbine stock once the proper tax stamp is in your possession.
- How long does shipping take to an FFL?
- Ironclad Armory processes in-stock firearms for shipping within 2 business days. Transit time via FedEx or UPS 2-Day Air is typically 3-5 additional business days to your selected Federal Firearms License (FFL) holder, but you must contact that FFL dealer beforehand to coordinate the transfer and their fee, which averages $25-$75.
- What is the thread pitch for muzzle devices?
- The barrel has standard 5/8-24 tpi threads, which is the common pattern for .30 caliber rifles. This accommodates a vast array of muzzle brakes, compensators, and suppressor mounts from companies like SureFire, Dead Air, and SilencerCo without requiring an adapter.