you wanted to know if someone could top 608 yards, well here goes. about 10 years ago at the local hang out we had our own spud launcher to play with. for propellant we used starter fluid and ignition was a standard grill lighter. the projectile was very specialized. it consiisted of a one foot long 3/8 by 3/8 piece of spruce main body with plywood fins sanded on the leading and trailing edge to stabalize it during flight. the nose was triple coated for protection and durability ans well as "armor piercing" capabilities. a wadding of paper towels taped to fit in the bore then coated in 3 in one oil. firing behind the local hangout unknown to us at the time over the mountain the dart was forgotten about as it went out of sight and being unable to recover it forgotten about. about 1 week later someone brought the dart back, it had been painted noen orange for visibility. it had landed in his grandmothers back yard aproxmatly one mile away. the gun itself had a 4in diameter chamber about 2 feet long and the barrel was 2 in diameter about 3 feet long. all made from schedule 40 pipe. in another test with a dart of the same design, fired at point blank range went through a 1in piece of ply wood.