Chrome moly barrels, are completely made of that material, while a chrome lined barrel is only --- chrome lined
Point is, that in a chrome lined barrel, the bullet only has contact to pure chrome, that is damn hard and corrosion resistant.
If you have the possibility, you should take the chrome lined barrel. I would say, that the barrel itself is also a chrome moly barrel, but the bore is lined, and therefor much more resistant to wear. If you want a rifle you can shoot many many rounds without significant barrel wear, take the lined barrel.
The barrel wear, I usually see on Swiss K31 Rifles. They mostly got used quite a lot in the army, and have a lot of wear, if the barrel wasn't already changed when they were taken off service and sold to the public.
(Ok, I have to admit, that the old Swiss GP11 ammo has Steel Jacket Bullets )