From this story in the Chicago Tribune:
Gun owners and potential gun owners are flocking to sheriff's offices across Iowa in the wake of a new state law that requires sheriffs under most circumstances to issue permits to carry concealed weapons. According to The Des Moines Register, several sheriffs' offices reported receiving 10 to 20 times as many applications on Monday as they do most days. The new law, which took effect last Saturday, limits the discretion local sheriffs previously had in denying permits without explanation. Now, sheriffs can only deny applications for specific reasons, such as a prior criminal record or drug and alcohol addiction, and must provide a written explanation.