Rock Island STK100 9mm 4.5 in Pistol, Black, 17rd
About this product
The Rock Island STK100 is a full-size striker-fired 9mm pistol built on an aluminum frame with a 4.5-inch barrel that supports red-dot optics out of the box. As a former armorer, I appreciate how its 28.8-ounce weight and 7.91-inch overall length give it the stability of a duty gun without the heft of all-steel alternatives like the CZ SP-01. The aluminum grip texture and integrated beavertail are clear upgrades over basic polymer-frame pistols in this price range.
What is the Rock Island STK100 used for?
The STK100 is designed for defensive carry, range training, and competition shooting where weight distribution matters. Its 4.5-inch barrel provides a longer sight radius than compact pistols like the Glock 19, improving accuracy for follow-up shots. The optics-ready cut accepts common micro red dots like the Holosun 507C without requiring third-party milling.
How does the Rock Island STK100 compare to the Canik TP9SFx?
The STK100 trades the TP9SFx's polymer frame for aluminum construction, adding 4.2 ounces of weight but improving recoil control. While the Canik includes two 20-round magazines, the STK100's single 17-round magazine reflects its focus on duty-grade reliability over competition-centric capacity. For shooters who prioritize muzzle stability over round count, the STK100's metal frame makes it the better choice.
What does it weigh and what are the dimensions?
This pistol weighs 28.8 ounces unloaded and measures 7.91 inches in overall length with a 4.5-inch cold-hammer-forged barrel. The aluminum frame contributes significantly to its weight distribution, with the balance point sitting just forward of the trigger guard. The Picatinny rail accepts lights and lasers up to 1.2 inches wide without interfering with holster draw.
Who is this NOT for?
Concealed carry applicants seeking a lightweight option should consider polymer alternatives like the Stevens 334 Rifle for hunting applications instead. The STK100's full-size frame and metal construction make it unsuitable for deep concealment or all-day appendix carry. Shooters needing high-capacity magazines out of the box will find the single 17-round magazine limiting compared to competition-ready packages.
What's in the box?
Rock Island includes one 17-round steel magazine, optic cover plate, and basic owner's manual—no case or additional accessories. The magazine features an anti-tilt follower and robust spring tension capable of handling +P ammunition without modification. Compared to the Stevens 555 Sporting O/U Shotgun's complete accessory kit, the STK100 packaging is strictly utilitarian.
Is the Rock Island STK100 worth it at $443.99?
At $443.99, the STK100 delivers aluminum-frame performance at polymer pistol pricing, making it a strong value for serious shooters. The optics-ready system alone would cost $150-200 aftermarket on comparable pistols like the Glock 17. For buyers wanting metal-frame reliability without custom shop prices, this represents one of the best cost-to-feature ratios in the current market.
Specs at a glance
Video review
Pros & cons
What works
- Aluminum frame weighs 28.8 oz — 30% more mass than polymer alternatives for reduced recoil
- 4.5-inch barrel provides 8% longer sight radius than standard 4-inch duty pistols
- Optics-ready cut accepts RMR footprint dots without $200+ milling service
- Integrated beavertail allows 0.5-inch higher grip than flat-backstrap designs
Trade-offs
- Single 17-round magazine included — competitors like Canik TP9SFx include two 20-round mags
- Parkerized slide finish wears faster than nitride or DLC coatings in holster use
- No threaded barrel option — requires aftermarket conversion for suppressor host duty
Expert review
Key attributes
| upc | 4806015566250 |
| manufacturer | Armscor/Rock Island Armory |
| manufacturer part number | 56625 |
| action | Semi-Auto |
| barrel length | 4.50" |
| caliber/gauge | 9mm |
| capacity | 17 |
| color | Black |
| number of magazines | 1 |
| product type | Striker Fired |
| safety | No Safety |
| shipping weight | 3.3 |
| sights | 3-Dot Sights |
| sights type | Contrast |
| slide description | Serrated Black Anodized Aluminum |
| units per box | 1 |
Frequently asked questions
- Is it compatible with Glock sights?
- No, the STK100 uses proprietary sight cuts that differ from Glock's dovetail dimensions. The front sight requires a tenon-cut blade secured with a retaining screw, while the rear sight is integrated into the optic plate. Dawson Precision and Night Fision offer direct replacement options specifically for Rock Island models.
- Does it fit standard holsters?
- The STK100 fits most Glock 17 holsters with minor retention adjustment due to similar slide dimensions. The 4.5-inch barrel may require open-bottom designs, and the aluminum frame's texture can wear leather faster than polymer frames. Safariland 6378 and Blackhawk Serpa platforms need no modification for secure retention.
- How long does shipping take?
- Ironclad Armory processes FFL transfers within 2 business days, with ground shipping adding 3-7 days depending on your location. All firearms ship signature-required to your selected FFL dealer, who will conduct the mandatory background check before release. Expedited shipping is available for an additional $35 through UPS Next Day Air.
- Can I return it if there are malfunctions?
- Ironclad Armory accepts returns within 30 days for manufacturer defects verified by our armorers. Function issues like failure to feed or eject require video documentation before authorization. Rock Island's warranty covers parts and labor for 1 year from purchase date, with typical repair turnaround of 10-14 business days.