I am thinking of converting a Sako S491 action to take a 22 Hornet.

Any suggestions would be much appreciated.

You might get a look at an Interarms MiniX in 22 Hornet and the same action in 223. The action sizes are similar to the Sako and both have fixed ejectors.

I've got a Mini Howa custom project that's very similar to the Sako. Biggest difference is the Howa has a spring plunger ejector. This is a problem with short cases like the Hornet or Fireball.