Taking a shot at you or your house would get them into trouble sooooo deep that they'd have to be mad to do it.
I consider myself a hunter. Check your state's game laws -- I'll bet that anyone hunting private property MUST get written permission before going onto the land. Photograph the person, their vehicle (if any), the license plate -- and use a camera that records the date and time whent he picture is taken. Use a new roll of film for this, and turn the UNDEVELOPED roll over to the authorities (mark it, and get a receipt for it from the cops -- this is called "continuity of evidence").
If you know where they usually come in, get some of that yellow caution tape and string it liberally around that area -- especially so that it frames your "No Trespassing" signs.
If this doesn't do it, there are cameras marked for hunters to take picture of game animals. You can use them to take pictures of illegal hunters, too.
They are probably doing this because they have always done it. 99% of the hunters out there are ethical and law-biding, and if you point out to them the error of their ways they'll change them.