50 yds is very doable with an A-5 and a flatline.  The flatline is a bit of a double edged sword.  Ya, it goes far...  The trajectory takes some getting used to though.
 
Well I already explained why that claim is BS.  I guess a Tipmann and a Flatline somehow are not effected by those pesky laws of physics.  Explain to me how this magical barrel makes paint fly farther????   Like I said velocity is the only way to get more distance, and if your shooting at > 300fps, you would get chewed out and kicked off of any field I've ever played at.  I don't know what you mean about trajectory either, trajectory has nothing to do with range or accuracy.   I can change the trajectory of any gun... ... it's called point it higher.  

I'm sure someone with more knowledge with ballistics would back me up here.   A .68 caliber, liquid filled ball, with a seam around it, and a muzzle velocity of < 300fps @150ft.  Like I said before that adds up to is a flight time of nearly a full second, and groupings of about 6ft if your lucky.  
I'd feel pretty dang confident behind a bunker, or sprinting @ 50yds with those facts.