Gearbox-developed looter shooter series Borderlands has made over $1bn in net bookings to-date.

That's according to publisher 2K Games, who revealed the milestone alongside the news that in excess of five million copies of Borderlands 3 have been shipped so far. Note that that doesn't mean that the game has sold that number of units just yet.

The company also says that 70 per cent of Borderlands 3 sales made within five days of its launch on Friday, September 13th were digital, the highest proportion for a 2K-published game to date. PC has been a sizeable factor in this, apparently, with sales on Epic's storefront described as "incredibly strong."

Last week, Gearbox CEO Randy Pitchford said that at launch Borderlands 3 on PC had double the peak number of concurrent users that its predecessor had. That means that there were around 248,000 people playing the shooter at one time.

“Borderlands 3’s incredibly successful launch is a result of the hard work and longstanding partnership between Gearbox Software and 2K,” said 2K president David Ismailer (pictured).

“We are immensely grateful to everyone who played a role in making the Borderlands series the global, pop culture phenomenon that it is today, including hundreds of developers at Gearbox and many who have made this their life’s work. We also want to thank the Borderlands community. Mayhem does not happen by itself, and their passion for the series is what drives us to make each game an amazing experience.”

At Gamescom, PCGamesInsider.biz caught up with creative director Paul Sage to find out how Gearbox had updated its looter-shooter for a modern audience and whether it saw titles like Destiny and The Division as rivals.