there are conversions on the 591/592 to ctr fire in 5mm RF (5mm craig) the 581 is a 22RF- there is new 5mm ammo out now I would not do it again- I would like to reconvert mine back to rf.
I would thread the reciever anyway, I made up a little recoil lug just like the 788's, although it wouldnt have to have one. I was thinking hornet, or 17 hornet as I miss the Kimber in that cal I sold. The 581 is the same action as the 5mm RF, and has been converted to centerfire, Saunders, who does all the 17 cal stuff has done them before.
Check the James Calhoon bullets site. Last I knew, he was selling plans and referring people to Dennis Olson for the conversion to CF. I did one myself in 22 K-Hornet and it worked out well. The action isn't long enough to eject a loaded round, but is otherwise trouble free. Google around for "5mm Craig" and you'll find a source for a conversion to the CF version of the factory round, although it's a bit pointless now that RF ammo is available.
