What is the best sniper scope to use with a Tippmann A5?

Generally without high quality paint-to-barrel match or first strike rounds, Magnifying scopes are near useless. A red dot or reflexive sight is preferred, but a low power 2X scope would be the best if you really wanted a cross-hair scope.

Maximum range in paintball is largely considered 150ft or 50yards, nothing that you would need a magnifying scope for are you can easily see that far with your eyes alone. Beyond that, paintballs are not the most accurate things either so even with really good paint and a really good barrel, a crosshair scope will only be telling you where the paint "might" go. The only way I would recomend a crosshair scope or magnification is if you are using first strike rounds as they will be more accurate and give you more range