My Type 99 has a chrome lined bore. The Japs were some of the first ones to start doing it to their battle rifles. While it is understandably not highly desirable on hunting rifles that only get a box of ammo per year and long range precision rigs that squeeze every bit of accuracy out of the rifle, I do think chrome lining would make a lot of sense on a Scout rifle, survival rifle, or something of that sort that might conceivably be used extensively in the field without much cleaning, and which doesn't require sub-MOA accuracy. But nowadays, I think nitriding makes more sense than chrome lining. It provides the same benefits but maintains a barrel's accuracy.