A jury at the High Court in Glasgow was shown CCTV footage of three masked men carried out the raid.
Alan Mitchell, 34, and Gary Mitchell, 20, deny robbing a quantity of watches from Eric N Smith Jewellers in Newton Mearns, Glasgow, on April 13, by brandishing a machete and hammers and smashing display windows.
Prosecutor Sheena Fraser played a clip of the raid, which lasted for 33 seconds.
Shop owner Yvonne Smith, 52, said: "The first thing I was aware of was a really loud bang. It was like a gun going off. I ran towards where the noise was coming from. There were three men coming into the shop."
She told the High court in Glasgow the man armed with the machete stood guard over them while the other two smashed a display window of Rolex watches.
Mrs Smith told the court that she thought Alan Mitchell was the leader and that Gary Mitchell "was the one with the machete".
The trial before judge Lord Jones continues.