Tampons are excellent first aid for GSW's. Don't push them into a wound (ideally) and secure it with a wrap (extremities) or tape well (trunk). If they expand, all the better. The first step to stop bleeding is to apply direct pressure, and the expansion would assist. For bleeding 1. apply direct pressure with sterile or at least clean dressing, 2. elevate the wound above the heart, 3. if you know where the artery that feeds the area is, and the bleeding hasn't stopped, "pressure point" on arteries, or even just above the wound (between the wound and the heart). The glamorous tourniquet is almost never needed if you've done the previous steps. In 30 years as an EMT, ER Trauma Nurse Specialist, CPR and First Aid instructor I have never seen a wound that required a tourniquet pre hospital. (We sometimes use them in the ER to stop bleeding while suturing). An ideal tourniquet would be a blood pressure cuff, since a narrow one would do further damage as a "crush injury." Except in the case of lawyers, IRS and NSA employees, in which case I urge you to always apply a tourniquet around the throat.
