Darly,

I agree that every method can turn out very good barrels. Much depends on how proper the various methods are applied, which steel is used, and so on. As for Steyr's twisting of the barrel, I read once about that, but it may well mean that the hammers rotate in a twist patters rather then that the barrel itself is twisted. Whatever they do, I once shot a Steyr P II sniper rifle, and it was an incredibly accurate gun.

It might be interesting within this context to hear from people who have experience with polygonal and gain-twist rifling (not methods of putting rifling in, but rather different types of rifling). I own an SVI handgun in 10 mm AUTO that employs a gain-twist barrel, and it is not only super-accurate, it is also much more shootable as the gain-twist cuts the twist induced sideways movement to the gun to almost nothing. (Gain-Twist means the bullet starts 'straight' and that the final twist is gradually reached towards the end of the barrel)