At local range past Sunday and fellow shooting couple of his T3's showed me a steel bolt shroud he had purchased for his rifles. Appear to be well made and said they came from Australia?? Failed to ask him the actual source and perhaps someone on this site has a lead for one??
As to why he replaced it, said that it broke on his rifle. Asked if he dropped the bolt and he said it broke when he chambered a 308 round in his 270 Tikka and fired the rifle!! Can't imagine the pressure spike, but said it spoke highly of the strength of the Tikka rifle. I would say he was very lucky. I have a Tikka T3 Tactical and that synthetic bolt shroud is about the only thing I would change on it. I don't have any plans on testing mine as this fellow did.

Don't take his advice !!