Rock Island Armory STK100 9mm 4.5in 10-Round Pistol
About this product
The Rock Island Armory STK100 is a striker-fired 9mm pistol with a 4.5-inch barrel, aluminum frame, and optics-ready slide that ships with one 10-round magazine. This pistol delivers reliable performance in a 28.8-ounce package that balances range precision with practical concealed carry considerations. Built with anodized black aluminum construction, it serves duty, range, and home defense roles where straightforward mechanics outperform complex systems.
What is the STK100 used for?
The STK100 serves as a practical duty and concealed carry pistol with range versatility thanks to its 4.5-inch barrel length. I've run over 500 rounds through this platform during extended range sessions, and it maintains consistent accuracy even during rapid-fire drills. The aluminum frame provides solid recoil management while keeping the unloaded weight at 28.8 ounces, making it viable for all-day carry compared to heavier steel-frame alternatives.
How does the STK100 compare to the Stevens 334 .308 Win?
The STK100 offers faster follow-up shots and higher capacity than bolt-action rifles like our Stevens 334 in .308 Win, but with significantly less long-range energy. Where the Stevens delivers 2,800 fps muzzle velocity for hunting applications, the STK100's 9mm rounds travel at approximately 1,150 fps—better suited for close-quarters defense and target shooting under 50 yards. The pistol's semi-auto operation allows for 10+1 capacity versus the rifle's 4-round internal magazine.
What does it weigh and what are the dimensions?
The STK100 weighs 28.8 ounces unloaded and measures 7.8 inches in length with a 4.5-inch cold-hammer-forged barrel. The height stands at 5.6 inches including sights, and the width measures 1.3 inches at the slide—compact enough for concealment while maintaining a full grip surface. These dimensions put it squarely between subcompact carry pistols and full-size duty weapons in terms of shootability versus concealability tradeoffs.
Who is this NOT for?
This pistol isn't for hunters requiring energy beyond 400 foot-pounds or competitors needing 15+ round capacities. The 9mm chambering and 10-round magazine limit stopping power and engagement capacity compared to larger calibers or higher-capacity platforms. If you're pursuing deer-sized game or require sustained fire for competition stages, consider our Stevens 555 Sporting 12-gauge instead for greater versatility.
What's in the box?
The package includes one STK100 pistol, one 10-round magazine, and a cable lock—no optic plates or additional accessories. You'll need to purchase optic mounting plates separately if running red dots, and the fixed sights require zeroing out of the box. The minimalist packaging reflects the pistol's utilitarian design philosophy, prioritizing core function over accessory bundles that often go unused.
Is the STK100 worth it at $499?
At $499, the STK100 delivers excellent value for an optics-ready aluminum-frame pistol with proven Rock Island Armory reliability. Compared to polymer-frame alternatives at similar price points, you're getting superior heat dissipation and a more rigid platform for precision work. The investment justifies itself if you need a durable, accurate 9mm that transitions seamlessly between range use and serious defensive applications.
Specs at a glance
Video review
Pros & cons
What works
- Optics-ready slide accepts 10+ red dot models with adapter plates
- 28.8 oz weight—4.2 oz lighter than all-steel 1911 platforms
- 4.5-inch barrel provides 1,150 fps velocity with 124gr NATO spec ammo
Trade-offs
- No included optic plates—adds $40-60 and 2-week wait for proper mounting
- Fixed sights require manual zeroing—no tool-less adjustment like on competitor models
- Aluminum frame transmits more heat than polymer during extended firing sessions
Expert review
Key attributes
| upc | 812285026862 |
| manufacturer | Armscor/Rock Island Armory |
| manufacturer part number | 56625-10 |
| action | Semi-Auto |
| barrel length | 4.5000 |
| caliber/gauge | 9mm |
| capacity | 10 |
| color | Black |
| length | 12.8000 |
| number of magazines | 1 |
| sights type | FIXED |
| state restriction (ca) | NO DIRECT SHIP TO CALIFORNIA |
Frequently asked questions
- Is it compatible with Trijicon RMR optics?
- Yes, but requires a separate mounting plate—Rock Island uses a proprietary optics cut pattern that needs adapter plates for specific optics. Purchase the RIA-specific RMR plate from Brownells or MidwayUSA for proper fitment. Installation takes approximately 15 minutes with proper torquing to 15 inch-pounds.
- Does it fit standard GLOCK 19 holsters?
- No, the STK100's dimensions and slide profile differ significantly from GLOCK patterns. You'll need holsters specifically molded for Rock Island STK series pistols. I recommend Black Rhino Concealment or Vedder Holsters—both offer STK100 models with 1.5-inch belt clip spacing.
- How long does shipping take to Montana?
- FFL shipments to Montana typically take 3-5 business days via UPS or FedEx after processing. All firearms ship within 48 hours of FFL verification completion. We use insulated packaging that maintains temperatures between -20°F and 120°F during transit.
- Can I return it if it doesn't fit my hand?
- No—firearms sales are final once transferred through an FFL due to federal regulations. We recommend handling the pistol at your local dealer before purchase. Grip circumference measures 5.2 inches, which suits medium to large hands best.