Some questions Gents as I am looking at converting a rook rifle back to 22 Hornet from 410.

1) What is diameter of the liner at the breech. Is the 410 chamber diameter or the full diameter of the rim plus a bit more.

2) At the muzzle end - again how much is reamed out here.

Walther in their catalogue do 5.6x50r barrel with 10mm outside diameter and a 22 Hornet in 10 or 12mm OD.

Can somebody who has a lined rook rifle, please post a picture of the breech end.

Many thanks