L.A. punk sextet Bad Religion have reenlisted guitarist/Epitaph Records owner Brett Gurewitz, who left the band in 1994 to spend more time running the premier U.S. punk label. And after seven years with Atlantic, Bad Religion have returned to Epitaph, which issued their first seven albums.The result is much like U2 embracing its “classic” sound on All That You Can’t Leave Behind. Bad Religion stick to the basics — the hook-heavy, hammer-to-the-brain assault that’s been their bread and butter for years.The Process of Belief is packed with speed-of-light outsider diatribes — several tunes clock in under two minutes — featuring a trifecta of buzz-saw guitars, jackhammer drums and stranglehold melodies. “Destined for Nothing” and “Supersonic,” in which vocalist Greg Graffin laments the acceleration of culture, will definitely satisfy old-schoolers. Yet beneath that ol’-time aggression lurks a surprising vulnerability and self-doubt. “Materialist” could be taken as Gurewitz’s mea culpa for getting rich off punk rock. The band also indulges in a bit of beer-clanking nostalgia, laundry-listing the good/bad old days on “You Don’t Belong.”“You might not think there’s any wisdom in a fucked-up punk rock song,” Graffin bellows. But after 20 years of mostly true aim, Bad Religion know better.