I cant say that I know how the Vortex increases accuracy, but I can tell you my modified M4 that has a Vortex is the most accurate carbine I have. I stronglt believe the Vortex is part of that. It is more accurate than my M4 witrh the Phantom.
The Vortex is the best at reducing flash. Numerous side by side tests have been done by members over the years and the Vortex always, always comes out on top. Granted, the Phantom is always a close second, but it is always second.
Some people may come on and warn you about how the Vortex's tines can mushroom out and/or break off. This was certainly a problem with their older offerings, in fact it happened to me once. However, the newer style Vortex is an improved design and it is much stronger and more durable. If you look at the mass of it, I think you too will believe it is stronger than the much thinner material in the Phantom.
Availability of the Vortex is not a problem at all. Just contact the manufacturer at
www.smithenterprise.com/ and pick yours up/ Brownells also carries the newest versions. Beware of fake copies and older versions found at gun shows etc.