thanks Pat, this is a everlasting arguement…. except one one side gets to argue usually, and that's the piston side. I have both, albeit in two totally different rifles. (20" Larue OBR, DI, set up as a "sass" with optics, prs, ect. and a 14.5" pws mk214 piston gun with irons and a light, more for a light battle type rifle.) I personally feel that for a civilian or hobbyist, the DI will never, yes never, fail you unless you don't care for your rifle for years! Even military usage will not encounter problems because they clean their rifles. I think the only real advantage piston guns may excel at is full auto use, where it will use it's strong points to keep the weapon cooler and cleaner in situations where thousands of rounds will be fired in a single session. just my opinions, coming first hand from what I have experienced. thanks for posting that, it should be interesting to hear everyones point of view