Subject: At what angle will a bullet ricochet off water?

I hunt turtles with a rifle.  If a fire a bullet at the turtle at a 
shallow angle and miss, the bullet will bounce off the water, creating a 
dangerous condition for any bystanders.  Experience tells me that at a steeper 
angle, the bullet will penetrate the water.
I want to know the smallest angle that the bullet will penetrate the water.  I 
am using a .22 magnum rifle bullet with a muzzle velocity of about 2500 feet 
per second.  I am shooting into a body of still, fresh water.  Is there an 
equation where I can simply plug in different velocities or other variables to 
compensate for changes I may make in my hunting?  How will variables I cannot 
control like wind and temperature affect the angle?  

Re: At what angle will a bullet ricochet off water?