We take cryptocurrency — so the coins you hold can buy real hardware.Pay in crypto, spend it on real hardware. Free insured shipping worldwide over $399. Plain, unbranded boxes, sent from Germany.Free insured shipping over $399. Your rate is locked for 30 minutes once checkout opens.Rate locked 30 minutes. Every item sealed, serial-checked and covered by a 24-month warranty.Sealed, 24-month warranty.

Saved items Sign in
Small metal castle nut with notched edges

Luth-AR

Luth-AR CS-02 Carbine Lock Ring Castle Nut

SKU CH-9AEJ-3GBD5

Secures the buffer tube on AR-pattern carbines with a castle-nut design

  • TypeOthers
  • Luth-AR manufactured carbine lock ring for AR platform builds
  • Castle nut design secures buffer tube during assembly
  • CNC-machined steel construction resists wear under recoil
  • New factory component for rifle maintenance or upgrades

Luth-AR CS-02 Castle Nut

The Luth-AR CS-02 is a carbine lock ring designed to secure a receiver extension on an AR-pattern platform. It is manufactured by Luth-AR as a replacement part for standard castle nut installations. The component is supplied new and intended for assembly or maintenance tasks.

Builders needing a castle nut

This part suits armourers or hobbyists completing a lower receiver build that requires a standard carbine castle nut. It does not suit anyone needing a complete receiver extension kit, a different thread specification, or integrated quick-detach sockets.

Highlights

  • Luth-AR manufactured carbine lock ring for AR platform builds
  • Castle nut design secures buffer tube during assembly
  • CNC-machined steel construction resists wear under recoil
  • New factory component for rifle maintenance or upgrades

Specifications

BrandLUTH-AR
TypeOthers

Questions about this item

Is the CS-02 castle nut the correct part for a standard carbine buffer tube?

The CS-02 is a carbine lock ring castle nut manufactured by Luth-AR for carbine buffer tube assemblies.

How does the castle nut function once installed on the receiver extension?

It threads onto the receiver extension and the notches accept a receiver end plate to secure the buffer tube in place.

Also in this aisle

People compared these

Same shelf, same checkout — eight coins and a 30-minute rate lock.