ProMag COL21 StandardBlued Flush Fit Detachable 5rd 223 Rem, 5.56x45mm NATO for AR-15

The ProMag COL21 is a 5-round detachable magazine purpose-built for AR-15 rifles chambered in .223 Remington or 5.56x45mm NATO. Built from heat-treated steel with a durable black oxide finish, this magazine delivers reliable feeding in the field without the bulk of higher-capacity alternatives. The flush-fit design keeps your profile compact, making it an ideal choice for precision shooting, hunting applications, or situations where a low-capacity mag makes sense for your mission.

ProMag engineered the COL21 to withstand harsh field use. The heat-treated steel construction resists denting and deformation during transport and deployment, while the black oxide finish protects against corrosion in wet or challenging environments. Whether you're running drills at the range, hunting from a tight blind, or building a specialized AR-15 setup, this magazine delivers the durability you expect from a quality steel mag.

The 5-round capacity pairs well with bolt-action-style shooting disciplines, hunting scenarios where lower capacity is preferred or required, or as a training/backup magazine. The detachable design means quick changes and easy maintenance—simply drop it out, clear the feed lips, and reload. At home or downrange, the COL21 performs without fuss.

Key Features

• Heat-treated steel construction for durability in field conditions
• Black oxide finish resists corrosion and wear
• 5-round capacity with flush-fit profile
• Detachable design for quick magazine changes
• Compatible with standard AR-15 magazines wells
• Reliable feeding in .223 Remington and 5.56x45mm NATO

Specifications

Frequently Asked Questions

Will the ProMag COL21 work with my AR-15?

Yes. The COL21 is designed to fit standard AR-15 magazine wells and is compatible with rifles chambered in .223 Remington or 5.56x45mm NATO.

What does flush-fit mean?

Flush-fit means the magazine sits level with the base of the magazine well, without extending below it. This keeps your rifle's profile compact and is useful for hunting, precision shooting, or tactical applications where a low profile matters.

Is the black oxide finish corrosion-resistant?

The black oxide finish provides protection against corrosion and wear during field use and storage. It's a proven finish for steel magazines in harsh environments.

Is this magazine suitable for training or backup use?

Absolutely. The 5-round capacity and reliable steel construction make the COL21 ideal for training drills, backup magazines, or hunting setups where a lower capacity is preferred.