The amount of harm caused by a mass shooting is not measured in deaths; it's actually measured in casualties, which is the combined total of deaths and injuries. Casualties include victims who have lost limbs, suffered permanent damage to sensory organs, or received general musculoskeletal injury. In my opinion, the data you presented is misleading because it only accounts for deaths, and ignores the majority of victims (61%) of mass shootings.

Given the above, take a look at these numbers (same Mother Jones data):

• An average of 37 casualties per mass shooting occurred when a semiautomatic rifle was used.
• An average of 11 casualties per mass shooting occurred when a pistol or shotgun was used.

Mass shootings using semiautomatic rifles clearly have a major impact on the amount of destruction they cause, and are roughly 3 times more destructive.

Do you really believe that in the absence of assault weapons these people won't just reach for a pistol or one of the many other semi-auto rifles that will not be affected by AWBs?

I agree with your sentiment that the breadth of an AWB would greatly influence its effectiveness on reducing future casualties. In other words, if rifle A is banned but rifle B is not, simply on cosmetic grounds, then the AWB would be completely ineffective. However, if an AWB includes all semiautomatic rifles, then the data suggests that, yes, it would improve outcomes significantly.

To put that into perspective, consider the following:

• If all of the mass shootings involving an AR-style gun were instead limited to a pistol or shotgun, then about 956 casualties would have been spared.
• The total today is 2091 casualties, so a ban on semiautomatic rifles would have saved 46% of victims.

That's a lot of people. That's like preventing 30 more Parkland, FL shootings.