I have the above rifle in 243 and the barrel is getting a tad tired. I have been offered a pulled Tikka T3 barrel which has only had 150 rounds through it and yes I do know the rifle it came from. I see that the Tikka has a 1" x 16 thread or 18TPI but for the life of me I cant find out the specifications for the FFV.
Serial number for the FFV is 500450 if that helps
Any help comments are welcome.

Cheers

I think they are the same as a small ring mauser. .988 ODx12 TPI. There's not enough meat on the Tikks barrel shank to turn it down & rethread.

I show a .985x12 and a 25.1MM or close to .985x12

The 1600 action is the same as a small ring mauser, .980"x12. The 1900 is metric or so I'm told. The Zoli clones may have a finer thread. Of course, many people confuse M25x1.5 as being 1"x16. It is closer to .985x16 which may account for the confusion.

The m96 has a thread of 25mm dia, a threadlength of 16mm and a pitch of 12 tpi
The 1600 is identical to the m96
The 1900 has the 25mm dia, 12tpi but a threadlength of 19mm. The Zoli is identical
The tikka is normally 25mm dia, 16 tpi, and a length of 25mm

All of the 96/1600/1900 with 55deg withworth for decent strength and fitt

Well I decided to go all silly and have a yarn to a gunsmith, Yes it will fit but an adapter will need to be made