Authorities said Fromholz and his girlfriend were at a ranch about 40 miles south of San Angelo preparing to hunt feral hogs when the rifle the singer was carrying slipped out the bottom of its case, hit the ground and discharged.
He later died of his injuries.
Fromholz is best known for his song “Texas Trilogy,” but Willie Nelson’s cover of Fromholz’s “I’d Have To Be Crazy” reached No. 2 on the 1976 country music charts.
Fromholz also wrote and produced songs for Lyle Lovett.
Texas Gov. Rick Perry named Fromholz Texas Poet Laureate in 2007.