norc M14 screw size ?

[Bazzoka_Joe]

does someone know what is the size of the allen screw that lock the castle nut on the flash hider ?

 

[Travis Bickle]

Are you talking about the allan screw just under the front sight blade?
If so it is 3/16
I think that is what you mean.

 

[raindog]

does someone know what is the size of the allen screw that lock the castle nut on the flash hider ?

The castle nut lock screw is a 3.5 X .60 mm metric thread on my Norinco flash hiders, and curiously, a 1/16" allen key fits best for removal.