An explanation, from a gun nut.

[ThoughtCriminal]

93. Incorrect and outdated data

For example the claimed increase in gun murders and armed robberies in Australia

You can look at the true numbers for yourself:

http://www.aic.gov.au/documents/0/B/6/%7B0B619F44-B18B-47B4-9B59-F87BA643CBAA%7Dfacts11.pdf

Homicides 364 in 1997 down to 260 in 2010
Armed Robbery 21,305 in 1997 down to 14,582 in 2010

There were increases from 1996 to 1997, but that was while the law was being implemented.

"The proportion of homicide victims killed by offenders using firearms in 2009–10
represented a decrease of 18 percentage points from the peak of 31 percent in
1995–96 (the year in which the Port Arthur massacre occurred with the death of 35
people, which subsequently led to the introduction of stringent firearms legislation)"

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You are trusting a bad source with predictable results.