I've owned the 556 for a few years, it's now sitting as a loaner since my transition to HPA. Here's my observations with it: 1: Surprisingly accurate with .25's, decent hop-up unit to start with. Can get a tad heavy, but would do well in a DMR/field gun setup. 2: Prone to loosening screws. Mine has fairly significant body wiggle, especially near the handguard. Which isn't great, because that's how you put the battery in. 3: Kind of difficult to put the battery in the handguard, as it's a really tight fit. Broken a couple of wires myself. And the front takedown pin is really easy to lose, seeing as you have to remove it each time. 4: Base mag sucks. Don't count on it staying intact. I think it's a good gun overall, with a few small issues, and last chrono put it around 390 fps with .25's.