The National Rifle Association accused the department of presenting a demonstration last week that exaggerated the firepower of assault weapons.
"Either it was deliberate of there was a complete lack of understanding of the entire issue as it relates to the legislation in Congress," said NRA Vice President Wayne LaPierre.
"It was never our intent to mislead anybody. It looked to me like the cameraman was aiming at the wrong target," Broward County Sheriff's spokesman Jim Leljedal said Wednesday.
The 1994 ban on 19 types of firearms will sunset next year unless Congress acts to extend it.
Gun-control supporters want it extended and broadened, but the NRA and its supporters want an end to it because they say it is pointless.
CNN broadcast a report last Thursday of a demonstration that intended to show the difference between assault weapons and conventional firearms.
A sheriff's deputy fired an assault weapon into a cinder block causing heavy damage. Then when he fired a legal weapon, it produced no damage.
The problem was that the deputy had switched targets and was firing into the ground.
A CNN spokesman said when CNN personnel figured out the demonstration was confusing, they told viewers about it.
LaPierre has appeared on CNN to discuss the report, and the NRA issued a statement decrying the demonstration.
Leljedal said though Sheriff Ken Jenne favors extending the ban, neither he nor anyone else in the department had any intention of misinforming the audience.
"They (CNN) wanted to talk about it, so we did, and on very short notice we got some guns out and we did some demonstrations for them," Leljedal said.
He said the cameraman focused on the concrete blocks, and "I thought someone was shooting at a mannequin and others were shooting at the ground."