Ten years ago when the Dropkick Murphys blasted out of south Boston, few would’ve guessed that working-class punks with progressive politics and a bagpipe fetish would ever rise from underground infamy to (relatively) mainstream success. But that’s just what this band has managed to pull off with a balls-to-the-wall ethos conspicuously evident on each of the 23 tracks on this second installment of the Singles Collection (subtitled B-Sides, Covers, Comps & Other Crap). Little-heard originals like the ferocious “On the Attack” and “Soundtrack to a Killing Spree” underscore the group’s well-documented hardcore roots, just as Irish-themed anthems like “The Wild Rover,” a traditional pennywhistle romp, affably meet expectations. But what’s most revealing about this comp are the cover tunes, which in addition to predictable homages to old-school punk heroes (Gang Green, Sham 69) and, of course, Pogues founder Shane MacGowan, include solidly rendered versions of classics by rock gods AC/DC, Motorhead, and Creedence Clearwater Revival. Clearly, it’s the Murphys’ willingness to go their own way that’s earned them due respect.