A recent article from The Firearm Blog referenced the Active Response Training article with regards to the number of weapons a police officer confiscated.
Out of curiosity, I looked at the FBI's UCR crime report.
From FBI's Uniform Crime Report 2015
Total number of murders: 13,455
Knives: 1,544 (11.48%)
Other Weapons: 1,671 (12.42%)
Hand: 624 (4.63%)
Guns: 9,616 (71.47%)
Out of Guns
Handgun: 6,447 (67.04%)
Shotgun: 269 (2.8%)
Rifle: 252 (2.62%)
Unknown: 2,648 (27.54%)
The numbers from the ART was
67 handguns (78.82%)
11 rifles (12.94%)
7 shotguns (8.24%)
While a direct comparison is not an easy task, it shows that the handgun is the weapon mostly used.
There are many different aspects to be looked at, but here is an intersting tid bit of information from 3:40 of the video.
It's not that there are 400 people shooting, but 40-50 individuals are the ones doing it.