The Timney AR-15 Drop-In Skeletonized Trigger (Timney part number 664S) is a small-pin trigger module factory preset to a smooth, crisp 4-pound pull. Installation is a genuine 100 percent drop-in job using the rifle’s existing hammer and trigger pins, and Timney’s proprietary design eliminates the pin rotation and walkout that cause creep and inconsistency in factory triggers. There is nothing to adjust once it is in, which keeps the process simple for builders who want a better trigger without learning a new tool. As with Timney’s other small-pin triggers, a thin aluminum shim under the trigger is recommended for polymer lowers to guard against wear.

Key Specifications

• Pull weight is factory set to 4 pounds, ready to shoot with no adjustment.
• This is the small pin (.156 inch) model, sized for most AR-15 lowers.
• The trigger shoe is skeletonized to cut weight while retaining a solid feel.
• It is a true drop-in trigger, using the rifle’s original hammer and trigger pins.
• Timney’s design eliminates pin rotation and walkout, a common failure point in factory triggers.

Frequently Asked Questions

What pull weight is this trigger factory set to? It ships factory preset to a smooth 4-pound pull with no adjustments necessary.

Is this trigger adjustable? No, it is a factory-preset, non-adjustable trigger, which keeps installation simple.

Do I need special tools to install this? No, it uses your rifle’s original hammer and trigger pins for a true 100 percent drop-in installation.

Buy the Timney AR-15 4lb Drop-In Trigger

Upgrade a gritty factory AR trigger to a clean 4-pound break without learning a new adjustment process. This Timney skeletonized trigger drops in using your rifle’s existing pins and is ready to shoot out of the box. Browse more of our AR trigger lineup and order from our Lubbock, Texas gun shop for fast, direct shipping.