IN A WORLD where every new rock 'n' roll band seems to be singing ever so earnestly about war, unemployment, religion and true love, the Rainmakers' Bob Walkenhorst is a welcome change of pace: a wise guy. Walkenhorst writes and sings about those same topics on the band's second album, "Tornado," but with a refreshing irreverence.

No sooner has he compared nuclear war to an old-fashioned Midwest twister than he is contemplating repopulating the planet with the young girl in his root cellar. "If heaven is guilt, no sex and no show," he suggests in another song, "then I'm not sure I really want to go." With a sneering chuckle, he advises all believers in romance to save their stories for the bartender and their crying for the theater.

The Missouri quartet backs up Walkenhorst's lyrics with music that is just as irreverent and hard-hitting. The rhythm section pushes with the no-frills attack of Midwest groups from the Detroit Wheels to the Silver Bullet Band. Steve Phillips' lead guitar lines have the same chuckling sneer as Walkenhorst's vocals. The new songs reflect the experiences of a heartland bar band that suddenly confronts the wider world on its first tour. If the songs are sometimes more glib than insightful, they're always funny and danceable.

THE RAINMAKERS --

"Tornado" (Mercury, 832 795-1 Q-1). Appearing with the Insiders Saturday at the 9:30 club.