What's the advantage of Ruger Mark III's fluted barrel?

[alvin]

Looks like Ruger Mark III has three major variations -- Standard (with Luger like barrel), Target (with bull barrel), and Hunting (with fluted bull barrel).

LGS salesman showed me another variation. It's grip is more like 1911, and the model name is indeed 22/45 I prefer Luger's grip angle, so I bought this one.