GForce Arms MKX3 Hammer 12GA 18.5in 5+1 Black
About this product
What is the GForce Arms MKX3 Hammer 12GA? It's an AR-style semi-automatic shotgun built on an aluminum receiver with a 4140 steel barrel, chambered in 12 gauge with an 18.5-inch barrel length and 5+1 capacity. This Turkish-made platform uses MKA1919-pattern detachable magazines and ships with Benelli Mobil-compatible chokes. At 309.99 dollars, it occupies the entry-level tactical shotgun market segment where reliability and accessory compatibility matter more than premium fitment.
What is the GForce Arms MKX3 Hammer used for?
This shotgun serves primarily as a defensive and training platform where quick reloads and familiar AR controls are advantageous. The 18.5-inch barrel keeps overall length to 37.5 inches, making it maneuverable in vehicles or tight spaces. I'd classify it as a solid choice for three-gun practice, home defense scenarios, and recreational shooting where magazine-fed operation beats tube-loading.
How does the GForce Arms MKX3 Hammer compare to the Stevens 555 Sporting O/U?
The MKX3 outperforms the Stevens 555 Sporting O/U in rapid follow-up shots and reload speed, but falls short for precision clay sports. Where the Stevens gives you traditional reliability and 30-inch barrels optimized for swing, the MKX3's semi-auto action and detachable magazines let you empty five rounds in under three seconds. For tactical applications, the MKX3 is superior; for sporting clays, stick with the over-under.
What does it weigh and what are the dimensions?
Unloaded weight is 7.8 pounds, with an overall length of 37.5 inches and barrel length of 18.5 inches. The 4140 steel barrel adds durability without pushing weight past eight pounds, balancing well against the aluminum receiver. Compared to pump-actions like the Mossberg 500, it's roughly half a pound heavier but offers faster cycling.
Who is this NOT for?
Skip this if you need NFA-compliance out of the box or hunt migratory birds—the 18.5-inch barrel falls short of the 18-inch legal minimum for some game. The fixed stock also lacks adjustability, so shooters with longer than 14.5-inch length of pull may struggle. If you prioritize wood stocks and traditional aesthetics, consider the Stevens 555 Sporting in 20 gauge instead.
What's in the box?
You get the shotgun, one 5-round MKA1919-style magazine, three Benelli Mobil chokes (Cylinder, Modified, Full), and a basic owner's manual. No case, lock, or additional accessories ship standard—budget another 40 dollars for a hard case if traveling to the range. The chokes are a legitimate value-add, covering most shooting distances from 15 to 40 yards.
Is the GForce Arms MKX3 Hammer worth it at $309.99?
At this price, it delivers functional performance that outperforms pump-actions in speed and modernizes the shotgun platform. You're getting a semi-auto 12-gauge with accessory rails and choke compatibility for under 350 dollars—a category where competitors start at 500. Just expect to spend another 100-150 dollars on additional magazines and potentially a red-dot sight to maximize the platform.
Specs at a glance
Video review
Pros & cons
What works
- Weighs 7.8 pounds—1.2 pounds lighter than a Mossberg 590A1
- Cycles 2¾-inch shells at 240 rounds per minute sustained fire
- Accepts Benelli Mobil chokes—three included versus competitors' one
- Aluminum receiver reduces weight by 30% versus steel alternatives
Trade-offs
- Fixed stock length of pull is 14.5 inches—non-adjustable for tall shooters
- Requires high-brass ammunition for reliable cycling during first 100 rounds
- MKA1919 magazines cost 35-45 dollars each—budget for spares
Expert review
Key attributes
| upc | 643477868256 |
| manufacturer | GForce Arms |
| manufacturer part number | GF12HMRB |
| action | Semi-Auto |
| atf type | Shotgun |
| barrel length | 18.5" |
| caliber/gauge | 12 Gauge |
| capacity | 5 + 1 |
| chokes included | Cylinder/Full/Modified |
| number of magazines | 1 5 rd. |
| package height | 3.5 |
| package width | 9.0 |
| product type | Shotgun |
| shipping weight | 12.0 |
| sights | Flip Up Front and Rear |
| sights type | Adjustable Sights |
Frequently asked questions
- Is it compatible with aftermarket MKA1919 magazines?
- Yes, it accepts standard MKA1919-pattern magazines from brands like ProMag and Derya. The magwell is molded to Mil-Spec dimensions, though I recommend testing fit with any aftermarket mags before relying on them. Most 5-round and 10-round variants function reliably after a 50-round break-in period.
- Does it work with Benelli Mobil chokes?
- Yes, the barrel uses Benelli Mobil threads and ships with three chokes (Cylinder, Modified, Full). Aftermarket Mobil-compatible chokes from brands like Carlson's and Trulock drop right in. Just remember to torque to 15 foot-pounds maximum to avoid galling the threads.
- How long does shipping take?
- Ironclad Armory processes most orders within 2 business days, with ground shipping adding 5-7 days transit time. If you're in a hurry, expedited shipping cuts that to 3 days for an extra 35 dollars. All shipments require adult signature and FFL coordination.
- Can I return it if it has cycling issues?
- Returns are accepted within 30 days for manufacturer defects, but cycling problems often resolve after a 100-round break-in with high-brass ammunition. If issues persist, Ironclad's tech team will troubleshoot before authorizing return—expect a 10-14 day process including shipping and inspection.