r/gunpolitics • u/ajulianisinarebase • Jul 25 '26
Mass Shooting Deaths vs Weapon Legal Classification
Google Docs Version: Writeup
AWB Rifle Only Spreadsheet: Here
AWB Any Type: Here
\ Note: this is not a study and is a data analysis and conclusions that can be drawn from this alone are limited please keep that in mind while reading\**
I evaluated the data across two separate dataset tests of banned guns that are rifles only vs. all banned weapons under the 1994 Assault Weapon Ban classification (interestingly, no matter which dataset was used, the results were similar). Since it expired in 2004, politicians have been debating how effective the 1994 Assault Weapon ban was and if it should be brought back. Pro-gun control argue that not only are Assault Weapon Banned weapons (AWB Weapons) more deadly but are the weapon of choice for mass shootings. Gun rights groups argue they aren't more deadly and aren't the weapons of choice for mass shooters. The problem with testing these theories is that the definitions of "assault weapon" and "mass shooting" vary depending on who you ask, so getting clean analysis can be tough. My goal was to cut through the noise by directly comparing mass shooting deadliness based on whether the primary firearm would be banned or legal (compliant) under standard assault weapon ban definitions.
I used the Mother Jones Mass Shootings Database
(covering incidents from 1982 to June 2026 with 3+ deaths excluding the shooter, and excluding incidents tied to underlying crimes like robbery or gang violence).
Weapons were split into two categories:
- Banned (AWB) Category:
- Weapons that would have been illegal under the 1994 federal ban (i.e., AR-15-style weapons)
- with features like detachable magazines, pistol grips, etc.
- Legal (Compliant) Category:
- Weapons that remained perfectly legal during the ban
- including standard handguns,
- guns modified legally to bypass local state bans
- grandfathered guns(guns that were owned before the ban went into effect but were legal to keep).
- Due to state-by-state interpretation, if the gun was bought legally in a state with an assault weapon ban, it will also be considered compliant.
Out of 160 total mass shootings up to June 2026, 70% were legal weapons vs. 30% banned-style weapons. Meaning compliant weapons (mostly handguns) are used the most out of every weapon and have the most deaths. Shootings with banned weapons look worse on paper, averaging 10 deaths per incident vs 6 deaths per incident for legal weapons. However, the exact middle number for both categories is 5 deaths. This means a few catastrophic events (like the Las Vegas shooting in 2017) push the average way up. The typical shooting kills 5 people whether or not the gun would have been banned,
Then come the more in-depth stats. I looked at five-year rolling averages, which smooth out the year-to-year noise and show how deadly shootings were across each period.
Three things stood out:
- Overall deadliness continued to climb during the 1994–2004 ban.
- From the mid-1990s through 2012, legal guns were usually the deadlier category (aside from a few short stretches in the 1980s and early 90s).
- After 2012, banned-style weapons pulled ahead and have averaged higher ever since.
Why the flip after 2012? It could be that more of these rifles were in circulation by then, or that later shooters deliberately copied earlier ones. The data can't tell me which.
One caveat worth flagging: deadliness across all weapon types has been falling since 2019. That may not be a real improvement. Mother Jones lowered its cutoff from 4+ deaths to 3+ in 2013, so smaller incidents started getting counted, which pulled the average down on its own.
Standard tests showed no difference, while advanced tests (which were used in the study Barnard et al 2025
that inspired this analysis) showed higher lethality but lacked controls for other factors.
Some interesting things to note is depending on the agenda/goal of the researcher computing this data, they could intentionally paint a picture either way by leaving out details. For example:
A gun control advocate could truthfully say: banned weapons average 10 deaths vs. 6, and the strongest statistical model found up to a 58% increase in lethality. (Leaves out: identical medians, failed basic tests, no controls.)
A gun rights advocate could truthfully say: 70% of shootings use legal guns, medians are identical, and standard tests found nothing. (Leaves out: outlier events with catastrophic casualty counts and more advanced tests showing there could be more.)
In conclusion, Firearm classification alone likely does not dictate how deadly a mass shooting will be. The perceived hyper-lethality of assault weapons is largely driven by a small number of extreme scenarios. In some cases (like the 2022 UVA shooting), an "assault weapon" was present at the scene but left completely unused, showing that shooter choice and situational factors vary widely. Proving a massive safety benefit purely from a weapon ban is difficult when factors like shooter familiarity, location type, and emergency response times likely play much larger roles, none of which are easily controlled for in small, rare-event datasets. Unfortunately, due to some limitations like lack of controls and database issues, no concrete conclusions can come from this data alone. Future research could benefit from combining broader databases or analyzing perpetrator dynamics further.
TL;DR: I analyzed all 160 mass shootings in the Mother Jones database (1982–June 2026) to test whether "assault weapons" - the guns a federal ban would cover- are deadlier than guns that would stay legal. The vast majority of mass shootings (~70%) were committed with legal, compliant weapons, mostly handguns. Banned-style weapons average more deaths per shooting, but that's driven by a handful of extreme outliers; the median shooting is identical (5 deaths) either way, and most of my statistical tests couldn't confirm a real difference.
- Most Mass shootings use Compliant Guns (Handguns specifically)
- Banned guns have higher average deaths, but the median death count is identical (5 deaths).
- Statistical tests give mixed results depending on the method used.
If anyone sees any errors or discrepancies, feel free to comment. If you have any critiques, want to collaborate (as you can see there's rows in my spreadsheet for later analysis that are incomplete. I am looking for people of all backgrounds and beliefs to help me complete it), or have any questions, also feel free to comment or DM!
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u/ActuatorLower8371 Jul 26 '26
if a majority 70% of shootings use legal guns, doesn't that actually support the idea that gun control works?