Benjamin Jorgensen, 38, and Donna Hayes, 36, were sentenced to seven and eight years respectively for the robbery in a Melbourne restaurant.
During the robbery, Jorgensen grabbed what he thought was a bag of money - only to find it contained bread rolls.
He also accidentally fired his gun, hitting Hayes in the buttock.
Judge Roland Williams described the two, who had expected to steal takings worth about A$30,000 ($26,000, £13,000), as a "pair of fools".
Hayes was hospitalised for a month as a result of her injuries.
The two pleaded guilty to armed robbery at the County Court in Victoria.
Almost feel sorry for this pair of idiots, jeeez lucky he didnt kill someone
