GLOCK 21 V MOS .45 ACP 4.60in Black (3) 13-Rd
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About this product
The GLOCK 21 V MOS is a full-size, optics-ready semi-automatic pistol chambered in .45 ACP with a 4.60-inch Glock Marksman Barrel, front slide serrations, a modular backstrap frame, and a slide pre-cut for MOS optics mounting. This configuration balances the heavy-hitting terminal ballistics of the .45 ACP cartridge with the modern practicality of a red-dot-ready platform, directly from the factory. It ships with three 13-round magazines, making it ready for a serious training session or defensive role immediately after the required FFL transfer.
What is the GLOCK 21 V MOS used for?
The GLOCK 21 V MOS is engineered as a duty, home defense, and competition-ready .45 ACP platform. Its primary role is to provide a high-capacity, reliably accurate handgun for users who demand the terminal performance of a .45 caliber round and the speed of a modern red-dot sight. The inclusion of three magazines supports extended range sessions or multi-stage competitions without constant reloading, while the 4.60-inch barrel provides a longer sight radius and improved velocity compared to compact .45 models.
How does the GLOCK 21 V MOS compare to the Springfield Armory XD-M Elite 4.5″ OSP?
The GLOCK 21 V MOS offers superior aftermarket support and holster compatibility compared to the Springfield Armory XD-M Elite 4.5" OSP. While both are optics-ready .45 ACP pistols of similar size, the GLOCK's MOS system has broader optic plate availability, and its frame design is supported by a vast ecosystem of parts, from triggers to suppressors. The Springfield's grip safety and slightly higher bore axis give it a different feel, but for an armor-issued parts compatibility and a simpler field strip procedure, the GLOCK is the more pragmatic choice.
What does it weigh and what are the dimensions?
Unloaded, the GLOCK 21 V MOS weighs 1.73 pounds (785 grams or 27.68 ounces), with a overall length of 8.03 inches and a height of 5.47 inches with a magazine inserted. The slide width measures 1.34 inches, which is standard for a full-size GLOCK frame, allowing it to fit most duty-sized holsters designed for models like the G17 or G22. The weight, while substantial for a polymer-framed pistol, helps manage the recoil impulse of the .45 ACP round during sustained fire.
Who is this NOT for?
This pistol is not for shooters seeking a lightweight concealed carry option or those on a strict budget for both the firearm and an optic. Weighing nearly 28 ounces unloaded, it's 10 ounces heavier than a compact GLOCK 30, and the MOS system adds at least $150-$400 for a quality micro red dot sight on top of the base price. If your primary use case is deep concealment or you're unwilling to invest in the optic ecosystem, a standard GLOCK 21 or a smaller 9mm platform like the Stevens 334 Rifle for a different application might be a better financial fit.
What's in the box?
The GLOCK 21 V MOS ships from Ironclad Armory with three 13-round steel-lined polymer magazines, a polymer bore brush and cleaning rod, a cable lock, a polymer MOS sealing plate, a set of modular backstraps (medium installed), and the standard GLOCK owner's manual and warranty card. Notably, the box does *not* include optic mounting plates—those must be sourced separately from GLOCK or third-party manufacturers based on the specific red dot model you intend to mount.
Is the GLOCK 21 V MOS worth it at $648.99?
At $648.99, the GLOCK 21 V MOS presents strong value for a shooter committed to building a modernized .45 ACP system. The price includes the substantial cost of the three magazines (a $120+ value separately) and the factory MOS machining, which typically adds $75-$100 to a standard model's MSRP. Compared to buying a standard GLOCK 21 and having a gunsmith perform a slide cut, this factory-ready option saves time, preserves the factory finish and warranty, and gets you shooting faster. For a hunter looking for a different kind of precision platform, consider the Stevens 334 in .243 Win as a dedicated rifle option.
Specs at a glance
Pros & cons
What works
- Includes three 13-round magazines — a $120+ value that supports extended training immediately.
- MOS slide is factory-cut and finished — saves $75-$150 and 2-4 weeks versus aftermarket machining.
- Weighs 27.68 oz unloaded — the mass aids in managing .45 ACP recoil for faster follow-up shots.
- 4.60-inch Glock Marksman Barrel — provides improved ballistic consistency over the standard 4.02-inch G30 barrel.
Trade-offs
- Does NOT include optic mounting plates — adds $25-$45 and sourcing time before you can mount a red dot.
- Fixed factory sights — will co-witness poorly with most micro red dots, requiring an immediate $80-$150 upgrade to suppressor-height sights.
- Full-size frame is not ideal for concealed carry — at 8.03 inches long and 5.47 inches tall, it requires a dedicated OWB or duty holster.
Key attributes
| upc | 764503068508 |
| manufacturer | GLOCK |
| manufacturer part number | UV2150203MOS |
| action | Semi-Auto |
| barrel length | 4.61" |
| caliber/gauge | .45 ACP |
| capacity | 13 + 1 |
| color | Black |
| length | 8.03'' |
| magazine included | 3 x 13-Round |
| model | 21 |
| number of magazines | 3 |
| product type | Semi-Auto Pistol |
| safety | Firing Pin/Trigger Block |
| shipping weight | 3.4 |
| sights | Fixed Glock Sights |
| sights type | FIXED |
| slide description | Optic Ready/Serrated |
| state restriction (ca) | NO DIRECT SHIP TO CALIFORNIA |
Frequently asked questions
- Is it compatible with Trijicon RMR optics?
- Yes, but not directly. The GLOCK MOS system requires a specific mounting plate, which must be purchased separately. You need GLOCK's MOS Plate #02 (sold separately for ~$25) to properly interface a Trijicon RMR or SRO with the slide's proprietary cut.
- Does this model have an accessory rail?
- Yes. The GLOCK 21 V MOS features a standardized Picatinny-style accessory rail (MIL-STD-1913) integrated into the polymer dust cover. This rail will accept weapon-mounted lights and lasers from brands like Streamlight, SureFire, and Crimson Trace without an adapter.
- How long does shipping take to an FFL?
- Ironclad Armory processes and ships in-stock firearms within 1-2 business days after order verification and compliance check. Transit time via common carrier (FedEx or UPS) is typically 3-5 additional business days before it arrives at your selected FFL dealer for transfer.
- Can I return it if it doesn't fit my hand?
- No. Due to federal regulations, Ironclad Armory cannot accept returns on firearms once the transfer to your local FFL has been initiated. We strongly recommend you handle a standard GLOCK 21 frame at a local dealer to assess ergonomics before purchasing the MOS version online.
- Does this work with Gen 4 GLOCK 21 holsters?
- Yes, with a caveat. The frame dimensions are identical to the Gen4 GLOCK 21, so it will fit most holsters. However, an optic mounted on the MOS slide will require a holster with an open-top design or specific clearance for the red dot sight's housing.
- What is the thread pitch on the barrel?
- The factory GLOCK Marksman Barrel on the V MOS model is not threaded. It is a standard, crowned 4.60-inch barrel. If you wish to mount a suppressor, you will need to purchase an aftermarket threaded barrel separately, with the common .578x28 thread pitch for .45 ACP.