Scottish soft drinks group AG Barr, the maker of Irn-Bru and Rubicon, reported a drop in sales in the third quarter but said its full-year outlook remains unchanged.Revenues in the 18 weeks to 30 November were 0.6% lower than last year on a like-for-like (LFL) basis. This compared with revenue growth of 5.4% in the first six months of the financial year.LFL comparisons have been adjusted for the effect of the loss of Orangina sales revenue after the early termination of its Orangina contract with the recently formed Lucozade Ribena Suntory Group.After 5.4% revenue growth in the first half, year-to-date revenues, excluding Orangina, were just 3.5% higher."As we anticipated, our revenue performance in the third quarter slowed somewhat from the very strong growth in the first half," Barr said."This was driven by lower promotional activity, wholesaler destocking and a very competitive price driven trading environment in a soft drinks market which was in revenue decline."The stock was down 0.5% at 597.48p in early deals on Thursday.