Hornady makes a brass headspace comparator kit that works well. Measure the brass that chambers easily against brass that does not. Then it's just a matter of die adjustment.
If you are already getting heavy cam-over with your press and still need to bump the shoulder more, you can get...
22-250 shoulder is 1.515, 22cm shoulder is 1.49.
While the difference is only .025, it's better to set back .06 or so (1 turn on a tikka), so you can true up any runout in the factory chamber.
Not as simple as just running a reamer in there.
Check your buttstock to tang fit on that, make sure you're getting contact with the rear of the receiver and not just the rear of the tang. Bedding it would be a good idea too.
Thanks to @nhenry for jogging my memory about this ebonizing stuff. I did a couple coats, then sanded it back for a distressed look. Not everybody's going to like it, but I'm not Ikea.
They're both nice guns. I'm not a fan of the mag tube on the lever action, but the action is smooth and has a decent trigger.
I don't really have anything negative about the single shot, other than pulling the barrel is a little weird.