Answered by Ustadha Umm Abdullah
I am a hunter and hunt ducks and pigeons with airgun. When I fire i say Allahu akbar.some times I dont get the time to proper slaughter the hunt because when i reach them they have already died. Muftis here told me that such meat is not halal as you have not properly slaughtered it.
In books of fiqh it is stated that if you have hit something with sharp edge it is good to eat.by sharp edge it will bleed same is the case with gun fire as it will also bleed.so why it is not halal as it will bleed as that of hitting it with something having sharp edge? both have same affect but different rulings?
If a person uses a gun or arrow to hunt an animal, there are 4 conditions that must be found in order for it to be halaal (lawful) to consume:
To recite Bismillah before or at the time of releasing the arrow or bullet.
The death of the animal was due to the wound caused to the animal and not due to the impact. Once the animal is shot, one should go in pursuit of the animal to slaughter it. To slaughter the animal if there are traces of life in it.
If a person recites Bismillah and shoots the animal, immediately thereafter, he should pursue the animal. If he retrieves it after it has already died, there is no need to slaughter it. The meat will be Halaal to consume and to give to others.
It is necessary to search for the animal after it is shot and to slaughter it. If one did not salughter the animal after finding it alive will not be permissible to consume.
The bleeding caused by the bullet or any other sharp object will only suffice in the case when the animal was pursued and found lifeless. 
Only Allah Ta’ala knows best
Ustadha Umm Abdullah
Checked and approved by Mufti Mohammed Tosir Miah
رد المحتار علي الدر المختار ج ٦/ص ٤٦٨