There are threads about the threading of said rifle and arguments have ensued over the 1/2x28tpi barrel threading. Basically, it's chop and thread or just chop and install, but obviously, you need a gunsmith to do that. The vortex works well. I am not sure if DLASKS' "Vortex" is an accurate copy though...at least, I can't tell. The degree of the real Vortex's twist is crucial to its performance part of which you can see in this video. With the real Vortex, the flash is gone completely: I only assume the same is true for the DLASK clone.
[youtube]YxSPgn0e1z8[/youtube]