One problem with high walls (and low walls) is with extraction. They don't have enough leverage to extract stuck cases, such as you get with hot loads. The extractor is also weak and prone to breakage. It's hard to get you fingers into a high wall to pull out a case that is not fully extracted, and if you are able to reach the case the sharp edges of the walls will eat the skin off your fingers. They are beautiful guns and fun to shoot but you will probably have to stay with light loads.