I am brand new to this website, and this is my first post. I have had firearms for over 50 years, and have quite a bit of general knowledge, but here is one thing that I am curious about. I have a chance to pick up a very nice, older Sig 220 in .45 caliber. I have been told that the older 220's have some sort of sheetmetal slide construction, and aren't as good as the newer ones with more modern slides. Is there any truth to this assertion? Thanks, in advance, for any facts or opinions you might have.