The discounter passed the milestone earlier this month, when its sales hit £10.9m, helped by the rapid rate of its store openings.
It has opened 50 stores in 2009, including 45 in former Woolies, bringing the total to 140, with a further five to open before Christmas.
"We are having a bit of a mad rush to get stores open before Christmas," said joint MD Simon Arora. "Over the past few weeks we have been opening at least two per week."
As a result of the store openings and the increased popularity of B&M stores, Arora estimated that sales for the year ending December 2009 would hit £450m up 75% on 2008.
It was too early to give an estimate of pre-tax profits, but they would be "significantly up" on the £14m recorded in 2008.
B&M Bargains is spending £25m on a new 620,000 sq ft distribution centre in Liverpool, which will open next year and run in addition to its 520,000 sq ft DC in Blackpool. It will shift its HQ from Blackpool to the new site in Liverpool.
"That investment demonstrates our confidence in our business model and its long-term future," said Arora. "We believe that once a shopper has visited B&M they will stick with us. We have been growing throughout the boom times as well as the recession, so we are not expecting an economic recovery to hinder our growth."