Decided to try something new. Been thinking about it for a long time, and a few weeks ago finally started. Modified and old pattern i came across, learned a ton and some better ideas for the next one. I'll bring it into the office and see if i can peak any interest.
They have 2 options, both 1 piece and a 2 piece. With the long action you may want to look at the 2 piece. The low should be fine for the 40mm objective. Let me see if i still have the sako recommendations.
I've used flitz to clean up the cylinder, i did read at one time that you dont want it totally smooth because it needs something to bite when it fires and expands, if I remember correctly.