AR-15 Hammer Spring

AR-15 Hammer Spring

The hammer spring is the part that drives the hammer forward when you pull the trigger. If it is weak, the hammer may not strike the firing pin hard enough for reliable ignition. This United Defense spring is a replacement for AR-15 owners who are rebuilding a lower, replacing a worn or lost spring, or keeping a spare in the parts bin.

Features

• Double-Torsion Design — Two wire coils are wound from a single length of wire, so the spring stores energy by twisting rather than compressing.
• Twin Coils — The coils sit on either side of the hammer and slide over the hammer pin, which keeps the spring centered in the lower receiver.
• Center Loop — A rectangular loop joins the two coils and presses against the hammer to push it forward.
• Straight Spring Legs — Two long legs extend from the coils and rest on top of the trigger pin, giving the spring its anchor point.
• Dark Finish — The wire has a dark gray finish, as shown in the photographs.
• AR-15 Pattern — Shaped to the standard AR-15 hammer spring layout used in the fire control group, the set of hammer, trigger, disconnector and springs inside the lower receiver.
• Single Spring — Each order is for one hammer spring.

Fit and Installation

Orientation matters with this part. The loop goes behind the hammer and the legs sit on top of the trigger pin. If the legs end up under the pin, the hammer will have little or no spring tension. Keep the hammer under control while you work, because it carries spring pressure once the spring is installed.