The basic rules in this regard are:
1. At the time of firing the gun the name of Allah should be taken.
2. Once the animal is shot one should go in pursuit of the animal to slaughter it.
3. If the animal is found alive it should be slaughtered.
4. If the animal is dead on arrival, it would be deemed to be halaal provided:
a) the animal died due to the wound afflicted and the loss of blood and not due to the sheer impact of the bullet.
b) One continued in pursuit of the animal after shooting it until it was found. If the process of searching for the animal was not continuous in that it was halted for even a short while, the animal will not be deemed to be halaal.