Kevyn Major Howard, best known for his portrayal as Rafterman in "Full Metal Jacket," has died, his family tells TMZ.

Kevyn died Friday in a Las Vegas hospital surrounded by friends and family -- his cause of death has yet to be determined, but he'd been hospitalized for weeks with respiratory issues, his family tells us.

Kevyn was born on Jan. 27, 1956 in Montreal, Quebec ... and with his dual citizenship moved to Los Angeles after college to pursue acting.

With dozens of film and TV credits to his name ... Kevyn appeared on screen with some of the biggest names in the biz, including Clint Eastwood, Charles Bronson, Frank Sinatra, James Caan, Mandy Patinkin, Don Johnson, and Matthew Modine.

As a matter of fact ... he and Modine stayed pals through the years after working together on "Full Metal Jacket" -- and the pair spoke on the phone shortly before Kevyn's death, his family told us. Matthew has been made aware of his passing.

In the Stanley Kubrick war classic ... Matthew, AKA Pvt. Joker and Kevyn's Rafterman played Vietnam War correspondents. In the climax of the film ... it is Rafterman who shoots a sniper before she can kill more of their squad ... with Joker ultimately finishing her off.

We caught up with Howard back in 2011 ... and, we chatted about the iconic film too. Check out the clip to hear what he had to say.

Kevyn is survived by wife, Tiffanie; his step-daughter, Kayla, his sister, Kim and his brother, Kelsey.

In lieu of flowers, donations may be made directly to FueledBytheFallen.org.

He was 69.