At Bristol Crown Court, Wilfie Isaacs Jnr, 22, described how he was shot and his father killed with the same weapon.
Tensions had been running high between the Broadway and Isaacs families, who lived at the Chubbard's Cross caravan site near Ilminster, for almost two years, the court has heard.
Charlie, John and Billy Broadway deny murder and attempted murder.
Bristol Crown Court has heard the shooting happened on 5 May, following an earlier violent altercation between Charlie Broadway, 24, his two brothers-in-law, Joseph Finney and Riley Jones, and Mr Isaacs, 49, and his son.
Charlie Broadway, Mr Finney and Mr Jones are accused of attacking Mr Isaacs Snr with a metal bar - causing a cut to his eye - after he complained some younger members of the Broadway family had been rude to him.
Prosecutors allege John Broadway, 37, known as Dewey, gave the order to younger brother Billy, 18, to get a gun who then passed it to Charlie to shoot the Isaacs.
Mr Isaacs said: "Everything happened so quick... [he] shot me in the shoulder. He was probably aiming for my head but I moved at the last minute. Then he shot my dad.
"After he shot me and my dad he aimed at my mum and my two-year-old daughter."
Mr Isaacs said he had not seen the black pump-action shotgun before but the Broadways were "always firing guns in the air".
Charlie and Billy Broadway also deny a charge of possessing a firearm with intent to endanger life.
Mr Finney, Mr Jones and Charlie Broadway also deny unlawfully wounding Wilfred Isaacs Snr and the assault occasioning actual bodily harm of his son.
Bonnie Wilson denies a charge of assisting an offender.
The case continues.
A man has described seeing his father being shot dead by a neighbour in their caravan park home in Somerset.