Having used both extensively I can sum it up with this. Do you want a 8-9 lb weapon loaded ready to go or a 11-12 lb weapon loaded and ready to go. Either caliber will hit and kill at 500. 5.56 is much easier/quicker in close quarters. Much cheaper to operate. 7.62 eats obstacles like walls and fenders and more effective on deer and large varmints past 400.... I would seriously consider chrome chamber and barrel... Or plan on EXTRA cleaning... Have fun and master S.P.O.R.T.S. Look that up and learn the system! It can save your life.
Good Shooting. Bricegun)