AR-15 Castle Nut

Why Choose the ATI AR-15 Castle Nut?

The ATI AR-15 Castle Nut is a replacement component designed for compatible AR-15 receiver-extension and buffer-tube assemblies.

It is a small but important part of the rear stock system, helping secure the buffer tube and related hardware in the proper position.

Secures the Buffer Tube Assembly

The castle nut threads onto the receiver extension and is used to secure the rear buffer-tube assembly against the lower receiver.

Proper installation helps keep the receiver extension and associated components firmly positioned during use.

Important Part of the Rear Stock System

Although compact, the castle nut plays an important role in the overall AR-15 stock and buffer system.

It works together with the receiver extension and locking plate to maintain a properly assembled rear-end configuration.

Useful for Builds and Replacement Work

The AR-15 Castle Nut is a practical component for a new build, buffer-tube replacement or stock-system repair.

It can also be useful when rebuilding an existing assembly where the original nut is damaged, worn or no longer suitable for reuse.

Works with Adjustable Stock Configurations

Castle nuts are commonly used with AR receiver extensions designed for adjustable stock systems.

This makes the ATI Castle Nut a useful supporting component when installing or servicing a compatible AR-15 buffer tube and stock.

Simple Component, Important Installation

Correct orientation and tightening are important when installing the castle nut.

The surrounding receiver-extension hardware should be properly positioned before the nut is secured to help ensure the complete buffer assembly remains correctly installed.

Confirm Buffer-System Compatibility

AR-platform receiver extensions and stock assemblies can vary depending on the firearm and configuration.

Always confirm that the castle nut is appropriate for the buffer tube and rear-stock system being used.

Always review the ATI Fitment tab before ordering.

The ATI Advantage

ATI offers individual AR-platform components that allow owners to replace only the parts needed during a build, repair or stock-system upgrade.

The AR-15 Castle Nut provides a straightforward replacement component for completing and securing a compatible AR-15 receiver-extension assembly.