Dungheap
Be sure to check out the total overall LENGTH of the ejection port of the 580/590 series rifle, very very little room to clearance, have to lengthen the bolt travel slot/stop locations.
I set the end of the chamber at the forward end of the ejection hole, so I could have the maximum clearance for the Kit Fox cases, (when I made the NEW bolt end).
I have a 591/2 that was done by one of our members into a 22 hornet, very little room for clearance/ejections of LOADED rounds, fired brass no problems.
This is now waiting for a 17 Weasel Hunter reamer to get here and be made into a new home for the G-son, unless Grandpa likes it.
Do some checking etc for total clearance of loaded rds, using the bolt stop position etc.
Don