The  Tippmann A5 Magazine Conversion kit from Tacamo turns you’re A-5 into a full-on mil-sim paintball gun that accepts detachable ammo magazines just like a real black rifle firearm.  This kit replaces both side of the  Tippmann A5 body.  Your existing gun internals stay in the paintball gun.  The kit comes with a 20 round detachable magazine.  Other magazine sizes (including a large 250 round box magazine) are available.   If you want to fire the gun in a traditional way, optional attachment s for both cyclone feeds and vertical feed hoppers are available separately.

The main advantage is a smaller profile and an increased line of sight.  There doesn't need to be a hopper attatched to the gun.  Also magazines are "force feed", which are better than gravity feed hoppers.