Armalite Ar 10 A2 Help

[Boe]

I know this may be a shot in the dark, somehow while shooting the Rifle my friends flash hider took a trip down range. Can't find it. I need help finding an original 7.62 splined flash hinder for a pre ban barrel. Armalite doesn't have one and no idea where to get one.
Any help or leads would be appreciated.
Thanks