(ShareCast News) - AG Barr was looking at slightly muted full year performance in a pre-close trading update on Friday, citing a challenging domestic market and its tough first half.The FTSE 250 soft drinks manufacturer - owner of the Irn-Bru brand - said it expected to deliver fourth quarter revenue growth in excess of 2.5%, which would be lapping the 5% growth seen in the corresponding period a year prior.Barr described the British soft drinks market as remaining challenging and competitive, but maintained its trading strategy, brand activities and execution were delivering a robust performance."Business performance has continued to improve across the second half of the year and revenue for the 53 weeks ending 30 January 2016 is now expected to be around £257m", the company's board said in a statement."On an ongoing basis, stripping out the effect of the 53rd weeks, revenue for the full year is forecast to decline approximately 1.5%", it added.Barr said its operational investments in efficiency and flexibility were continued to make good progress, and all of its current projects were set to be delivered on time and within budget."Having dealt with the challenges of the first half, and successfully managed the festive trading period we are on course to meet our expectations for the year", the board said."While trading conditions are expected to remain challenging, we are confident that the combination of our strong and flexible business model, our differentiated brands and our well-invested asset base will allow us to deliver further long-term business success", it concluded.AG Barr planned to announce its full year financial results on 29 March 2016.