AR-15 Bolt Catch Spring

AR-15 Bolt Catch Spring

This United Defense spring sits under the bolt catch in an AR-15 lower receiver. The bolt catch is the lever on the left side that locks the bolt open after the last round. The spring holds that lever down while you fire. When the magazine runs empty, the follower pushes the catch up against the spring and the bolt stays open. A tired, kinked or lost spring can let the bolt lock back early or fail to lock at all, and a fresh one fixes that. It is a small part worth keeping in a builder's parts bin or a range bag repair kit.

Features

• Bolt Catch Return Spring — Keeps the bolt catch down during normal cycling so the bolt only locks open when the magazine is empty.
• AR-15 Pattern Fit — Made for the bolt catch spring pocket in AR-15 pattern lower receivers.
• Compression Coil Design — A straight wire coil that pushes back as it is squeezed, which is the job the bolt catch needs done.
• Closed Coil Ends — The last coil at each end is closed off, giving the spring a flat seat against the plunger and the receiver.
• Bare Metal Finish — Plain, uncoated wire with nothing to flake off inside the receiver.
• Repair Or Build Part — Replaces a worn, bent or lost spring, or completes a lower parts kit during a build.
• United Defense Manufactured — Produced by a commercial parts maker as a direct replacement component.

Fit and Installation

The spring goes into the hole beneath the bolt catch, with the bolt catch plunger on top. The bolt catch then sits over both and a roll pin holds it in place. Most people use a roll pin punch and a bit of patience, because the spring is small and easy to lose during assembly. Check that the bolt catch moves freely and snaps back down before you reinstall the upper.