The original barrel was well past its best and I had it replaced by Fulton's of Bisley. I use it for local service rifle competitions, although it has never really shot well. On average it'll keep most shots in the black at 300yds (we're talking a pretty large target/scoring zone).
I took it out this weekend and had trouble just keeping the shots on the target board (300yds). The grouping was very erratic, left and right, high, low, etc. This is with good quality ammunition, the same load the majority of us use for .303
British
(Viht N140 -39.5gns, 174gn SMK, Privi cases, standard Remington primers).