lurkso: Whether or not the drop in the crime rate, especially the overall murder can be attributed to more guns or not is debatable .. However since the murder rate has been decreasing steadily while gun ownership has gone up shows that more guns does not lead to more murders.
Selectively picking mid 90's as the start year produces that result for you, but guns have increased about 300% (quadrupling) since the early 60's -- that big bulge in the center of the gun death bell curve is the quarter million gundeaths since early 60's, dwarfing 9/11, pearl harbor & all the school shootings combined.
.. The murder rate in 1962 was about 4.6 (guns ~3.0), stayed above 8.0 from 1971 - 1995 peaking at 10.2 in 1980, all while guns were tripling from 75 million to ~225 million.
.. From early 60's to mid 1970s both the national gunstock & the murder/gunmurder rate doubled (75 million to 150 million guns, 4.5 to ~9.0).
.. Certainly other factors play into it, drugs as others mentioned, lead in gas & paint etc, but guns enhanced the carnage.
In early 1960's the national violent crime rate was 160, then guns doubled & tripled & the violent crime rate peaked at 758 in 1991 & stayed above 500 for over 20 years.
.. In 2011 the violent crime rate rests at 386, a 150% increase from 1960's, while national gunstock went from 75 millions to ~300 millions.
.. Duh, the bigger picture MORE GUNS MORE CRIME. (this applies to both progun states & gc states, with few exceptions like NY & VA).
http://www.disastercenter.com/crime/uscrime.htm
But, adherents to the 2nd Amendment Mythology manipulate facts to their propagunda all the time - whereas, while total guns in USA have indeed increased to 300 million, the personal gun ownership rate has dropped from over 40% last century down to ~33% now, which is the better explanation why murder rates & violent crime rates have fallen since mid 90's.