Smooth One,
I don't know who THE GURU of Beretta tuning is, but they sure slipped past my radar. The gunsmith who developed the match upgrade for the Beretta M9 - 92 and who still does a whole lot of Berettas is still up and running. Dave Sams developed the Beretta upgrade for the AMU under Colonel Mack Johnson and that same Beretta is the one that Tony Kidd did for a while, the AMU still uses, and many Beretta tinkerers have tried to figure out. George Harris, Asst. Director of Training at SigArms Academy, and an Army reserve marksmanship unit MSG, is the one who introduced me to MSG Sams, and from what I have seen and shot, Dave does a pretty damn fine Sig tuning, too.
FYI:
http://www.louderthanwords.us/forum/vie ... ms+beretta
http://www.gun-tests.com/performance/oc ... etter.html
http://www.army.mil/soldiers/sep97/text/newstxt.html#8
http://www.samscustomgunworksusa.com
I have had the oppurtunity to study, very closely, the Beretta that Dave Sams builds, as well as talk to many of the people at AMU who were there while he developed the gun, to include the man who gave the order, and everything I have found says that he is THE GURU of Beretta tuning... and Sigs, too. FWIW, he builds some of the most accurate 1911s anywhere, and his rifles are found all over the world in long-range accuracy matches.
Hope that helped.
~Jim Keeney