The Artifact perk Piercing Sidearms does not work on the new Indebted Kindness special ammo sidearm. Other sidearms of various types appear to be unaffected. Upon shooting barriers such as Scorn shields, Taken Phalanx shields, and Cabal Phalanx shields, no damage numbers or "immune" appear and the shots do no damage. Work as normal on enemies without similar shields. EDIT: It does appear to work fine on Barrier Champion shields, it just doesn't appear to have the extra functionality vs other shields like those listed above