How long does it take for gangrene to develop in a leg after a gunshot in a diabetic person?

Diabetes . It is not typical for gangrene to develop with most GSWs .diabetics are at higher risk due to poor circulation on a capillary level. Dead tissue or certain aggressive bacteria can lead to gangrene. And this can be with Hours to days to weeks. Follow with a surgeon experienced in GSWs to avoid developing it in the first place .
Depends. Diabetic ulcers do take a long time to heal if blood sugars are chronically elevated.
Too many factors. I have seen gas gangrene develop in 18 hours. Other gangrene can take longer. Give me more info.
24 hours to never. In this scenario gangrenr results from a vascular injury or a large amount of devitalized tissue. An arterial injury would lead to gangrene faster than a variable amount of devitalized tissue from the blast injury.
No much difference. Look at it this way. Gangrene can develop after a gunshot wound to the leg whether the victim has diabetes or not. A diabetic person can develop gangrene in the leg whether he has sustained a gunshot or not. It is simply a matter of uncontrolled blood sugars, an impaired or unsustainable vascular tree and a host of other co-morbidities.