ar style castle nut

An AR style castle nut is a steel locking nut used to secure the buffer tube (receiver extension) to the lower receiver on AR-15 and AR-10 rifles. It threads onto the buffer tube, holding the end plate in place and ensuring a stable, secure connection. The AR style castle nut works with AR-15/AR-10 lower receivers, carbine-length buffer tubes, end plates, buffer assemblies, and collapsible stocks. It’s essential for building or maintaining reliable, adjustable AR-platform stock setups.