I start these once in a while when I get a few ideas:
Apart from guns that occassionally jam or backfire (based on some statistical probability).
How 'bout a OFP soldier damage model.
For example, depending on the cause of injury, we could have:
* Severed legs (caused by an explosion, eg: being fired at by an RPG or stepping on a land mine)
* Mangled body (caused by helicopter crash)
* Severed hand/arm (caused by your weapon backfiring)