Glock Model 21 Factory Magazine .45 ACP 13-Round

Glock Factory Magazine for Model 21 .45 ACP

This is a factory original magazine engineered specifically for Glock Model 21 .45 ACP pistols. Like all genuine Glock magazines, it combines proven reliability with practical durability.

Construction and Design

Glock magazines feature a hardened steel insert encased in advanced polymer. This design provides several advantages:

• Durability: The polymer coating protects the magazine body and prevents deformation, even when dropped from significant heights
• Reliability: Drop-free design ensures smooth feeding and reliable operation
• Capacity: 13-round magazine holds a full combat load for the Model 21

Break-In Period

New Glock magazines may feel stiff when loading. This is normal and expected. The factory recommends:

• Load the magazine with all but the last round and allow it to sit for several days so the spring can compress
• Cycle the magazine repeatedly from full to empty to accelerate the break-in process
• After a brief break-in period, the magazine will load and function smoothly

This initial stiffness is a sign of quality—it ensures consistent spring tension throughout the magazine's service life.