There seems to be a slight flavor of piston vs DI in this thread. There is a difference and most people are here because they like the piston operating system but everyone needs to keep in mind the DI system works fine, specifically those that are made with quality parts by quality people. I've been running DI guns since 1987 and have been an armorer for them for years as well as a rifle instructor. They work if you half ass take care of them. I prefer LWRC's piston, it's reliable and clean and fun to shoot. But I would use a properly made DI gun in a second if I couldn't use a piston. So in other words, let's not argue about what's better, they both work.
Write drunk; edit sober - Ernest Hemingway