The era of the Bruins power play as league-wide punch line might finally be coming to an end. It was a constipated unsightly run last season for the Bruins. They ranked 26th in the NHL with a 14.8 percent success rate during the regular season and they have ranked in the NHL’s bottom third of power play success percentage in three of the last four seasons. During the playoffs the Bruins have scored on only 13.2 percent (23-of-174) power plays over the last three seasons but have still managed to get to the Stanley Cup Final twice in that period. The Bruins are enjoying success anyway but it boggles the mind to think what the Black and Gold might be capable of if they were cashing in on the man advantage on a regular basis. One could actually envision it in the later rounds of last year’s playoffs when Torey Krug injected a little life into Boston’s power play squad and the B’s ended middle of the road with 11 PP goals in 63 tries for a respectable 17.5 percent success rate. But things haven’t consistently been productive for Boston’s special teams since Marc Savard was brained by Matt Cooke four years ago. That could all change heading into this season however. The Bruins served notice by dropping four power-play goals on the Montreal Canadiens in their first exhibition game last week and they’ve continued to look confident productive and smooth on the man advantage through camp practices and subsequent games. “I think our power plays look pretty good so far" coach Claude Julien said. "Preseason is preseason and not all the teams have their best penalty-killers out there but I’ve liked the puck movement. I’ve liked the results . . . In every power play we seem to at least get something out of it. So hopefully that continues.” Having the mobile hard-shooting Krug for a full season and the signing of Jarome Iginla certainly look like they’re going to change things for the Black and Gold. Iginla provides the Bruins with that righty shooter from the left face-off circle that they’ve lacked over the last few years. Instead of Tyler Seguin or Rich Peverley going high glass with every bid from the “Stamkos spot” in the middle of the left circle Iginla is shooting daggers at the open spots on the net.