In an IDEAL world, you would have .452 cylinder and .452 barrel - good luck on finding that combination in a production gun.
A 2nd IDEAL situation would be .454 cylinder and .454 barrel - that's the original Colt configuration.
A cylinder that is .001 over the barrel is as close to IDEAL as I hope to see - the real question is not what size are they - the real question is "does it shoot"
Some revolvers with a cylinder several thousanths larger than its barrel still shoot like hotcakes. You have what appears to be a tight barrel. What that really translates into is more velocity with less powder as the pressure will build faster. A lot of 357's have barrels as tight as .354 - they still shoot factory ammo..
The real problem comes in to play when the barrel is larger than the cylinder - that doesn't appear to be your situation at all.
If the end of your barrel is "actually" smaller than the slug you get from the barrel, than you could improve things by lapping the barrel. The most fun way is with a box or two of cartridges and a jar of JP paste. The quiet way is with a ramrod and a tight patch with JP paste. Not as much fun, but totally effective. Do it until you get the dimension you want.
I would shoot it 'as is'. Your cylinder is a couple thousanths larger than you barrel. All is tight. That is good. IF you put a .452 bullet, with lube all over it, into the cylinder, it should be a snug slip fit - if they are both .452 - if it still goes with a great deal of force, either the cylinder is smaller than you measured, or the bullet is larger.
Have fun and stay safe - and shoot it.
