If .200 was taken off the breech, there should have been something more done. If not, I would be concerned that everything is in sync.
I feel fairly confident that you can take .100 of the breech of a 10/22 barrel and have the bolt close properly. Anything more than that, there needs to be some things to consider. Bolt closing over the breech, extractor slot depth, V-block locking up the barrel to receiver, etc.
You can't just take .200 off the breech of a barrel and call it "good"! There are too many other variables to consider. I've "trimmed" a couple of barrels & re-chambered to find out out later that there were other things to consider. It is possible & can be done....just needs to be thought through and a "Well Known Smith" may not get you there.
Reducing the chamber depth by taking some off the breech of a barrel may not allow the bolt to close fully.
If you take .200 of the barrel breech in a 10/22, there's not a lot of barrel protruding into the receiver for the bolt to close over.
Reducing the chamber depth and then trimming the barrel shoulder that butts to the receiver to accommodate the reduction may not allow the V-Block to secure the barrel in the receiver adequately.. Comes up short!
Reducing the chamber depth by shaving the barrel breech, also requires you to re-cut/modify the extractor slot.
It's very easy & possible to shave the breech of a 10/22 barrel (I've done several), but you have to address the areas of the barrel that the reduced dimensions affect
I've gone as far as to shave the front of the receiver where the V-block snugs to.
Its Possible.........but there are other things you have to consider to make it all work. Just Proceed with some caution & think about how all the dimensions come together. Take off .100 and I think every thing is good. more than that........better be paying attention!