M4-Style 400E 100 BB Magazine

Type: BB magazine
Manufacturer: Barra Airguns
Capacity: 100 steel .177 cal (4.5mm) BBs
Compatibility: Intended only for the 400e air rifle; not compatible with other ammo types
Body: Durable polymer housing
Mechanism: Spring-fed follower; tension increases as the magazine fills
Maintenance instructions: If jams happen, place a single drop of silicone oil on the follower and allow it to sit overnight

A Backup magazine that extends range time and practice drills for users of the 400e air rifle. Capacity of 100 steel .177 cal (4.5mm) BBs removes frequent reload interruptions during sessions.

Low-profile M4 silhouette pairs well with tactical-style handling and quick-change routines. Fill with a BB speed loader; stop once loading resistance rises to avoid spring damage.

Pros:

• M4-shaped magazine for natural handling and quick swaps
• Sturdy polymer housing made for repeated use
• Internal spring follower for smooth, continuous BB feed
• Speed-loader friendly for fast top-ups between drills
• Easy remedy for jams: one drop of silicone oil on the follower overnight

Cons:

• Polymer body can scuff or wear with heavy use.
• Spring tension rises as it fills — risk of overfilling and jams.