HK Extended Castle Nut Compatibility with AR-15 Buffer Tubes

Is the extended castle nut seen on the HK 416A5 compatible with Mil-Spec buffer tubes? What's the purpose of the extended castle nut? In this video I attempt to answer both these questions and show a few different Mil-Spec buffer tubes and how they work with the HK castle nut.

Timestamps
0:00 - Introduction
1:05 - Mil-spec buffer tube
3:02 - Enhanced buffer tube
4:48 - Function check
7:40 - Why use an extended castle nut?
9:25 - Conclusion

Originally uploaded on YouTube: 2022-08-06
Recording date: 2022-07-28