CHATTANOOGA, Tenn. (AP) _ Former Auburn University football star Bobby Hoppe's murder trial for a 1957 shooting ended in mistrial when jurors declared themselves deadlocked.

Prosecutor Tom Evans said he got a measure of satisfaction when Hamilton County Judge Joe DiRiso declared the mistrial Wednesday. ''The defense was entering this case with the idea that it wouldn't take long to reach an acquittal. They were wrong.''

Hoppe was on trial in for allegedly using a .410-gauge shotgun to kill Don Hudson, a 24-year-old moonshine runner, 31 years ago. The state contended Hoppe, then a 22-year-old halfback at Auburn, was angry because Hudson had beaten Joan Hoppe Voiles, Hoppe's sister and Hudson's ex-girlfriend.

But Hoppe testified during the seven-day trial that he shot Hudson in self- defense on July 20, 1957, after the bootlegger drove up beside his car on a dark North Chattanooga street and pointed a pistol at him.

The jury deliberated for four hours before declaring itself hopelessly deadlocked. Two jurors later said the vote was 10-2 for acquittal.

Hoppe, 53, declined comment afterward. DiRiso said a new trial date would be announced July 25.

''My immediate reaction is I'm disappointed,'' said Leroy Phillips, one of Hoppe's attorneys. ''I wanted a verdict. It was a hard-fought case, and I wanted a verdict. And I was entitled to one.''

The statute of limitations has expired for all possible charges in the slaying except first-degree murder, meaning Hoppe could not face a lesser charge unless he waived that time limit. He refused to do that during his trial, instead taking his chances against the 20-year-to-life sentence that a first-degree murder conviction carried under state law in 1957.

Hoppe, a halfback on Auburn's 10-0 national championship team in 1957, was indicted March 2 after police reopened the case at the request of Hudson's mother.

It was the first time anyone had been charged in the killing, although Hoppe had been linked to the slaying at a 1957 coroner's inquest and during a 1966 grand jury probe.

Since the indictment, Hoppe has been on unpaid leave from his position as athletic director at Chattanooga State Technical Community College.