| Industrial-grade steel nuts for a rock-solid buffer tube assembly. Proudly Made in the USA. |
Steel Castle Nuts for AR-15 and AR-10 Buffer Tube Assemblies
The castle nut secures the receiver extension (buffer tube) to the lower receiver and, together with the end plate, locks the assembly in place on AR-15 and AR-10 builds. This five-pack of steel castle nuts is suited to new builds, replacements, and keeping spares on the bench for multiple projects. Made in the USA, each nut is intended to hold the buffer assembly tight and resist loosening under repeated cycling.
Castle nuts are commonly staked to the end plate after installation to help maintain torque over time. Pair these with an AR15 mil-spec end plate or an ambidextrous dual loop end plate to complete the lower assembly.
Before ordering, confirm the nut matches your buffer tube and end plate so threads and fitment line up with your platform, and use a proper castle nut wrench for installation and torque. While you build, restock small parts like the buffer retainer spring ten-pack.
Specifications
| Material | Steel |
| Finish | Phosphate coated |
| Specification | Mil-Spec dimensions |
| Compatibility | Fits all standard carbine buffer tubes; AR-15 and AR-10 builds |
| Weight | 0.6 ounces (per nut) |
| Staking | Notched for staking |
| Quantity | Five pack |
| Origin | Made in the USA |
Frequently Asked Questions
This is a five-pack of steel castle nuts. Each nut secures the receiver extension (buffer tube) to the lower receiver and, with the end plate, locks the buffer assembly in place. The multi-pack suits new builds, replacements, and keeping spares on the bench for multiple projects.
These castle nuts have mil-spec dimensions and fit all standard carbine buffer tubes on AR-15 and AR-10 builds. Before ordering, confirm the nut matches your buffer tube and end plate so threads and fitment line up with your specific platform.
They are made from steel with a phosphate coating and are built to mil-spec dimensions. Each nut weighs 0.6 ounces and is notched for staking. All are made in the USA and intended to hold the buffer assembly tight and resist loosening under repeated cycling.
Yes. Each nut is notched for staking. Castle nuts are commonly staked to the end plate after installation to help maintain torque over time. Use a proper castle nut wrench to install and torque the nut before staking.
Pair a castle nut with an end plate to complete the lower assembly. Options include an AR15 mil-spec end plate or an ambidextrous dual loop end plate. Confirm compatibility with your buffer tube before ordering.