Montrose reached the peak of their commercial popularity during the Warner Bros Presents and Jump On It era from 1975 to 1977, which found the band adhering to a grueling tour schedule across America and Canada, performing predominantly in large arena and stadium venues sharing the bill with major artists that included The Rolling Stones, Kiss, Peter Frampton, Yes, Rush, The Eagles, Journey, and Aerosmith, as well as headlining their own shows in mid-size arenas. This period also netted Montrose their second highest chart position, with Warner Bros Presents reaching No. 79 on the Billboard 200. As the result of a near-fatal amphetamine overdose during his stint with the Edgar Winter Group, Ronnie Montrose observed a strong personal anti-drug/anti-alcohol stance during this period, exemplified by his insistence that all Montrose band members abide by a strict policy of drug and alcohol-free performances. After the departure of vocalist Bob James following the band's performance at Winterland on December 31, 1976, Montrose imploded as a group and Ronnie Montrose resurfaced a year later with the solo instrumental album Open Fire, released in January 1978. During this period the guitarist also worked with jazz-fusion drummer Tony Williams. In 1979, along with Montrose holdovers Jim Alcivar and Alan Fitzgerald, drummer Skip Gillette, and Scottish vocalist Davey Pattison, Ronnie Montrose formed a new group in the progressive hard rock mould named Gamma. The band's debut, Gamma 1 was released in 1979. Their second release, Gamma 2 (1980), saw former Montrose drummer Denny Carmassi replacing Skip Gillette and bassist Glenn Letsch replacing Alan Fitzgerald, who went on to become a founding member (as keyboardist) of Night Ranger. After Montrose Sammy Hagar went on to build a successful post-Montrose solo career which, during its early phase, featured fellow former Montrose member Bill Church on bass and drummer Billy Carmassi, younger brother of Montrose drummer Denny Carmassi. Hagar had many successful albums with top hits such as "Your Love Is Driving Me Crazy", "I Can't Drive 55", "Heavy Metal" and "There's Only One Way To Rock". In July 1985, Hagar joined Van Halen. In 1987, Ronnie Montrose formed a new lineup of Montrose with singer Johnny Edwards and drummer James Kottak (both from the band Buster Brown), and bassist Glenn Letsch, who had replaced Fitzgerald in Gamma. This lineup of the band released one album, Mean (1987). Kottak would go on to join German hard rock bands Kingdom