ProMag COLA16B StandardBlack Detachable 42rd 5.56x45mm NATO for AR-15, M16
- Capacity-Rounds:
- 42
- Type:
- Magazines
- Firearm Group:
- AR Platform
- Caliber-Gauge:
- 223 Remington / 5.56 NATO
- Finish-Color:
- Black
- Model:
- Standard
- Material:
- DuPont Zytel Polymer
- Model Fit:
- AR-15
The ProMag COLA16B is a 42-round detachable magazine built for AR-15 and M16 platforms chambered in 5.56x45mm NATO. If you run a modern sporting rifle and want extended capacity for range days, tactical training, or competitive shooting, this magazine delivers nearly double the rounds of a standard 30-round mag without the footprint bloat of some alternatives. ProMag manufactures and assembles these in the USA, so you're getting a domestically made product backed by their lifetime guarantee against manufacturer defects.
The build is straightforward and robust. Springs are precision wound from heat-treated chrome silicon wire—the good stuff that resists fatigue and maintains reliable feeding cycle after cycle. Every magazine goes through multiple quality checks during assembly, not just spot-checked. That attention to detail matters when you're counting on a mag to run hard at the range or in the field.
Loading 42 rounds is intuitive; the design doesn't fight you. Capacity this high makes sense if you're looking to minimize magazine changes during extended shooting sessions, whether that's zeroing, drill work, or just stretching your range time between reloads. The black finish is durable and low-profile, fitting standard AR furniture without fuss.
Key Features
- 42-round capacity for AR-15 and M16 platforms in 5.56x45mm NATO
- Heat-treated chrome silicon wire springs for reliable feeding and durability
- Manufactured and assembled in the USA
- Lifetime warranty against manufacturer defects
- Easy-loading design with rugged construction
- Multi-stage quality control during assembly
Specifications
| Capacity | 42 rounds |
| Caliber | 5.56x45mm NATO |
| Platform Compatibility | AR-15, M16 |
| Magazine Type | Detachable |
| Finish | Black |
| Spring Material | Heat-treated chrome silicon wire |
| Manufacture | USA |
| Warranty | Lifetime (manufacturer defects) |
Frequently Asked Questions
Will this magazine fit my AR-15?
Yes, the COLA16B is designed for AR-15 and M16 platforms chambered in 5.56x45mm NATO and uses standard detachable magazine compatibility.
What makes ProMag springs different?
The springs are precision wound from heat-treated chrome silicon wire, which resists fatigue better than standard spring material and contributes to reliable long-term feeding performance.
Is there a warranty on this magazine?
ProMag backs the COLA16B with a lifetime warranty against manufacturer defects, so you're covered for defects in materials or workmanship for the life of the magazine.
How difficult is it to load 42 rounds into this magazine?
The magazine is designed with easy loading in mind, so filling it to capacity is straightforward without requiring excessive force or special tools.

