Reading the title "Using my horse Pasture as a shooting range" made me think of the line "Oh George ... Not The Livestock!" from the fim Oh Brother Where Art Thou
Seriously.
The city blue book makes it an offense for projectiles (rocks, arrows, bullets) to cross property lines and a worse offense if they cross public thoroughfares.
At the old family property on the mountain I make a point that firing lines for target practice must be away from the road and the bullets must land on family property. When people are heard driving down the country road, ceasefire until they are past and around the bend.
The guy shooting at a target on the fence line with the bullets landing on the neighbor's pasture is incredibly rude in my not so humble opinion. I was taught it is better in life to try to make allies not enemies. This guy is just making his life and others' lives more miserable (and dangerous) by being an irresponsible derriere.
I am just prattling about what's right and wrong. What's legal and illegal are often different from right and wrong.