Most likely belonged to a USN corpsman attached to USMC units.  Possibly flying aboard rotary wing / tilt rotor aircraft.  Is there a tag inside the bag with a contract date?  Does the bag have a zipper with metal or plastic teeth?  They style of bag seems to have been introduced around 1969 with a lightweight metal zipper and then a heavier metal zipper introduced during the 1970s.  The plastic zipper seems to have been introduced around 1987.  I had one in the past that had Velcro closure on the top with a white towel cloth type lining.  Have had ones with poncho liner material linings both in camouflage and olive drab.  Also, had one with a black lightweight lining, possibly a foreign issue.  Forgot when the metal snap hook came into use.  Probably during the 1970s.  I am almost certain that the one with the black lining had a black plastic snap hook that swiveled.  There are also copies of this type of bag made commercially since the 1980s and come in many different colors and camouflage patterns for the outer bag material.

 

20 hours ago, amateuraero said:

Most likely belonged to a USN corpsman attached to USMC units.  Possibly flying aboard rotary wing / tilt rotor aircraft.  Is there a tag inside the bag with a contract date?  Does the bag have a zipper with metal or plastic teeth?  They style of bag seems to have been introduced around 1969 with a lightweight metal zipper and then a heavier metal zipper introduced during the 1970s.  The plastic zipper seems to have been introduced around 1987.  I had one in the past that had Velcro closure on the top with a white towel cloth type lining.  Have had ones with poncho liner material linings both in camouflage and olive drab.  Also, had one with a black lightweight lining, possibly a foreign issue.  Forgot when the metal snap hook came into use.  Probably during the 1970s.  I am almost certain that the one with the black lining had a black plastic snap hook that swiveled.  There are also copies of this type of bag made commercially since the 1980s and come in many different colors and camouflage patterns for the outer bag material.

 

 

I should have clarified, lol, it was mine.  I got it after after I got my NACS qual in the late 90s and did enroute care as a corpsman.  Later on I used the same bag when I was an enroute care RN.  I have been out for a long time but I still use the bag.