I own a few 1911 variants and I've fired a few dozen others over the years, but they've all had flat mainspring housings. I've seen a few arched ones, but I've never had the opportunity to fire one. I also noticed that almost all the 1911's on the market come from the factory with the flat style. What's up with the 1911A1 Arched housings, does anyone use them anymore? Are there any benefits to them or was it just a fashion thing that went out of style?