I'm new to this forum but have looked at it from time to time. When I saw this thread I thought I'd add what I have. I also have a Mitsui imported SKB 400, mine has 2 3/4 inch chambers and is in IC/Mod. Like Eddie K, none of the information I could find made any sense. As a matter of fact he and I spoke to each other on another forum about these guns. I did not know he had made the Mitsui connection. This has been my go to all weather gun for about 10 years.