Hi, according to the Viht. reloading chart, the suggested COL of the 6.5x55 is 80 mm./3.150" with the 123 Scenar bullet; that leads to a shank seat depth of a mere 2.6 mm./0.1". In your opinion, is this enough?

For me it would be no. I like at least one bullet dia. in length to be seated into the neck.

Forget book OAL, do what you need to do and develop your load around it.

I would check the length of the brass.
2.6mm is not a lot of case neck to grasp the bullet securely.
This seating depth will work at the bench target shooting. But I wouldn't want to take it hunting.

muck

I forgot to say it's a bench target load and I chamber each round manually....