I've compared the barrel nuts for Daniel Defense rails.
Basically, the Madbull one is smaller which will work on GBBRs.
The AEG clone ones are longer a bit to fit AEG barrels.
If you throw on the AEG barrel nut onto the WE GBBR, the barrel will be loose.
As for the front end cap as I stated before. It won't fit on the DD Mk18 rails period.
This is the RS version. Notice no end cap.
Basically, remove the end cap, and keep your triangle sight.
