I dont know how it is for people who have been shot, but at least as far as for a Parachute accident:
I was given a certain time to heal, when I was not 100% by the alloted time a Medical Retention board was held. The board decided that retraining in another job in the military was not going to fix the problem so I was given a disability rateing for the specific problems associated with the para accident, and a disability severence pay.
The severnce pay was figured by the ammount of time I had on AD, my base pay and a mulitplyer.
I then went to VA and they looked at the Med Boards findings, plus my medical records and determined my final disability rateing.
I receive a tax free payment each and evey month that is tied to my disability rateing. I also receive free medical care from VA for the rest of my life. A combat wounded vet is not set for life in most cases, but they are taken care of.