Got a rifle here someone else built in 6mmx300RUM the barrel has 100 rounds throught it and the firecracking goes from throat to crown. If you look real hard there is still a little of Liljas good rifling still left in there in places.
The owner told me he did get 4500 fps from the few bullets that made it through the Chrony. Seems like awful expensive shootin to me getting that little barrel life for the costs involved.