A painting of Jesus is thought to have been shot while it was hanging on the wall of a Cotswolds church.
An interpretation of The Last Supper, featuring a black Christ, has been on display in St George's Church, Nailsworth since 2010.
Artist Lorna May Wadsworth noticed a hole in the 12ft (3.7m) by 3.5ft (1m) picture while moving it to put on display in an exhibition in Sheffield.
She said she "never dreamed" anyone would react "so violently" to it.
Ms Wadsworth said pictures had been shown to a ballistics expert who told her it was a "perfect match" for air rifle damage.
She was "absolutely devastated" and "in shock" to discover the damage, she said.
She added a friend had pointed out that the painting had been damaged "at the exact point the Roman soldier pierced Christ's side to check he was dead".
"I was always aware that [painting a black Jesus] might be controversial, but I never dreamed that anyone could have a reaction that was so violent."
The vicar of St George's, the Reverend Caroline Bland, said she did not know how the damaged was caused, while treasurer Miles Robinson added he was "staggered".
"I've looked at the picture over a number of years and it's not a smooth surface, so from the oil side you don't obviously see it," he said.
My Last Supper altarpiece has been brought to Sheffield to form the centrepiece of my retrospective GAZE at Graves Gallery @MuseumSheffield from St George’s Church Nailsworth in the Cotswolds. When prepping for the… https://t.co/hjdKAfV2oX— Lorna May Wadsworth (@Lorna_May_) November 6, 2019
Security arrangements may now have to be changed at the building, which is currently open during the daytime, Mr Robinson added.
The picture is to be shown in an exhibition of Ms Wadsworth's work at Graves Gallery in Sheffield starting on Saturday.
Other notable works by the London-based artist include portraits of Baroness Thatcher, former Home Secretary David Blunkett and the former Archbishop of Canterbury Dr Rowan Williams.