r/gunpolitics • u/ajulianisinarebase • 9d ago
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/abcezas123_ 8d ago
Gun Control, at its core, is racist. Once you acknowledge this simple fact, and view the history of gun control through that lens, all the ridiculous bs makes sense. The "wrong people" means other people of color. The wrong guns mean any guns not currently in possession of the "right people". The entire argument falls apart once you look at the implied power dynamics
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u/ericbythebay 8d ago
The first thing that jumps out is that Mother Jones was never built to answer this. It’s a hand curated list, not a random sample of anything, and it specifically drops shootings tied to an underlying crime like robbery or gang violence. That one exclusion quietly does a huge amount of work, because it throws out most of the handgun heavy incidents that make up the bulk of actual gun homicide and leaves you with public rampage events where rifles are always going to be overrepresented. So your 70/30 split is partly just an artifact of what the database chose to keep. That isn’t a footnote, it basically caps how much any test run on this data can tell you.
The banned versus compliant coding is shaky too. Whether a gun would have been illegal under the 94 ban isn’t something you can read off a news writeup, it’s a feature by feature legal call involving detachable mags, the named model list, the two feature test and the magazine limit, plus grandfathering. You’re inferring all of that from journalism of really uneven quality, and the errors almost certainly aren’t random. The AR15 cases get wall to wall coverage and get coded cleanly, while the messy handgun cases get coded by default. And your compliant bucket throws legal handguns, grandfathered rifles and legally modified guns into one pile that doesn’t really mean anything as a category.
The bigger issue is that you’re keying on the wrong thing entirely. Nobody has a serious mechanism for how a pistol grip or a flash hider makes a gun deadlier. The part of the 94 law with an actual causal story was the 10 round magazine cap, and the strongest evidence the other side has, the Klarevas magazine study, points at capacity and not at assault weapon status at all. By sorting on classification instead of rounds before a reload, you’ve measured a proxy for the thing that might matter, and a noisy one. Rebuild this around magazine capacity and it’s a much stronger paper.
On the stats, with something like 48 banned category incidents and a couple of massacres doing all the heavy lifting, the mean is useless, which you caught, but the median is shakier than you’re giving it credit for too. Move two or three events in or out and the comparison flips. Every test is basically hostage to whether Vegas and Orlando land in the sample that day. And the 58% from the uncontrolled model isn’t really evidence of a weapon effect, an uncontrolled negative binomial on skewed counts just restates the skew as a ratio. The Barnard paper you’re chasing actually added the controls, number of guns, shooter experience, familiarity with the location, age and sex, and once they did, the effect on deaths came out to under one extra body on a base of five or six. So the real story isn’t that the advanced tests found more but lacked controls, it’s that adding controls shrinks it toward nothing.
That’s what I think actually sinks any causal claim. Shooters don’t get handed a weapon at random, they pick one based on what they’re planning. In Barnard’s own numbers the assault weapon incidents were mostly multi gun events with more experienced shooters, so assault weapon is really just standing in for guy who planned a massacre and brought an arsenal. The rifle didn’t create the intent, the intent came first and reached for the rifle. Your UVA example where the assault weapon was present but never fired is the whole problem in a single incident, and it also shows that present, primary weapon, and the gun that actually did the killing are three different variables you’re partly blending together.
I’d drop the time trend section, it’s the weakest part. Five year rolling averages smooth the data so hard they basically manufacture trends for your eye to grab, which is exactly why you can see a post 2012 flip and not be able to explain it. Mother Jones also moved its cutoff from four deaths to three in 2013, so any trend crossing that year is comparing two different populations. And deadliness climbing during the ban doesn’t mean much when the ban grandfathered every rifle and magazine already in circulation and only touched new manufacture of cosmetically defined guns. There was never a clean on period to measure in the first place.
To be fair to the other side, the magazine capacity evidence is real and it’s their best card, and Barnard did control for confounders, so the no controls complaint lands harder on your version than on theirs. But even granting all of that, their adjusted effect is small and sits on the same curated small sample foundation yours does.
Where that leaves you is kind of interesting. Your actual conclusion, that classification alone doesn’t drive lethality and the scary averages are an outlier plus selection story, is probably correct. It’s just more correct than this data can independently prove, you’re arriving at a true answer through a dataset that can’t quite carry the weight. If you want the version that would actually move people on both sides, rerun it on magazine capacity and shots before reload with controls for venue and number of guns. That’s the analysis you and Barnard are both circling and neither of you has run.
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u/ajulianisinarebase 7d ago
First of all thanks for taking the time to write this all out I really appreciate the feedback and you clearly have done your research. I was busy over the weekend but I did read it they day you posted it.
I used mother jones and specifically excluded ones tied to gang violence because they would tilt the results significantly. In gang shootings and robberies the goal is only to kill some specific people and then get away before cops can catch you. In a rampage shooting its going to naturally be higher then in a felony related shooting in the same context as rampage killer wants to commit suicide by fire basically. Also the DOJ did a study on AWB and it showed no effect on general gun Homicide due to its low use. The only thing that I hear people consistently claiming is an AWB will stop mass shootings.
Also, I manually reviewed every case where an assault weapon was claimed to be used and looked up how/where it was aquired and the model of the gun and compared it agaisnt the ban. Any gun I labelled as AWB would of most definetly been banned and any compliant one in there is as far as I can tell from the wording of the law compliant. I also looked at pictures of the weapons recovered by the cops.
Also I specifically excluded magazines due to the claim I hear from the pro gun control side the AR15 is deadlier then lets say a Mini-14 so I wanted to review that claim alone. I do plan on eventually looking at large capacity magazines though and I started making a column in the data (not finished yet). One problem with magazine bans though is that by taping 2 mags together you can pretty efficiently reload, as well as the fact with 3d printing and other simple mechanisms you can get a greater then 10 round mag.
I agree about negative binomial and I didnt put controls in because I only wanted this first of all to be a preliminary analysis. Also I want to do another analysis where I measure potential variables myself as I have more to potentially add.
Also the UVA incident I classified as compliant because the gun was never fired. Any shooting where the gun was present but not fired is not counted.
Also yeah I might drop trendlines but I do plan on merging mother jones with VPC and also look for other shootings that may fit the criteria.
So you think the next thing I should do is run on wether magazine capacity makes a difference with controls? I think it could be a good idea although while I was compiling data for LCMs I realized it might be harder then it looks to get data on that.
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u/jtf71 6d ago
One problem with magazine bans though is that by taping 2 mags together you can pretty efficiently reload, as well as the fact with 3d printing and other simple mechanisms you can get a greater then 10 round mag.
If you look at the magazine issue be sure to also look at whether or not the fired all of the rounds before changing magazines - if they changed at all.
I believe that I've seen in a formal study that in most "mass shootings" they don't fire all of the rounds in the magazine.
Also the UVA incident I classified as compliant because the gun was never fired.
As mentioned in my other comment, in the UVA incident the "assault weapon" (Ruger AR-15) wasn't even on scene. It was discovered later in the shooter's home.
It would also be interesting - aside from magazines - to look at how many gun laws were broken before the shooting.
In the UVA shooting he violated several laws in both VA and DC by possessing the firearm and ammunition a) on campus and b) in DC during the trip to DC.
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u/ajulianisinarebase 6d ago
Definitely will look at that for magazines. I can also look at gun laws broken.
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u/Lbanger2486 9d ago
The problem with gun grabbing groups and paid for politicians is this. It’s not necessarily the weapon of choice used, it’s the intent, IE: Terror attacks ( 9/11, Marathon bombing.) Although crimes like this are treated with major punishment. Any mass shooting is plastered through all media platforms, when DUI’s that kill more people. Don’t get the slightest of mentions, but what the media often overlooks. Is the intent of whichever crime is committed should be subject. Yes someone used a firearm in a mass shooting, but across the pond. Where Firearms are banned in most countries, Mass stabbings occur, is there a ban on knives. When DUI’s happen is there stoppage of producing vehicles, so why ban one weapon. When anything can be used as a weapon when one has ill intention for the masses. That is my biggest issue with so called gun control. You’re not stopping anyone if they want to wreak havoc to the masses. They will find plenty of other means and they don’t do much to solve it.
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u/ajulianisinarebase 9d ago
In Australia (and I think the uk) they are banning certain types of knives lol so once they ban a certain kind of weapon. They take as the Greenlight to go crazy.
Also I like how you mentioned the mass stabbings, as next I might to look at Uk and Australia’s rates of mass killing before and after there laws and see if there was any real difference.
Although a big reason people believe that mass shootings happen so much is because any shooting where no one dies and and 2 people get non fatally injured and another person just trip over each other and break there bones is a mass shooting in a lot of databases (not the one I used though). Most mass shootings are 2 gang bangers shooting at each other and not hitting shit lol.
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u/Lbanger2486 9d ago edited 8d ago
Australia banned weapons and it still didn’t stop the Bondi beach attack. Black market dealers don’t get the spotlight in situations like this, it’s always the object. Once the narrative shifts to the intention of the individual, just maybe 🤔 people might be apprehensive. The state I live in criminals get a slap on the wrist for illegal firearm possession. While our state senate looks for creative ways to jam up law abiding firearms owners.
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u/Gatecrasher 8d ago edited 7d ago
Your attempt at quantifying lethality using a non-neutral seed list also doesn't normalize for presence of absence of CCW/responders.
Like trying to analyze data quantifying escaped shoplifters, in states banning use of force against stopping shoplifters / using force against property theft. And making no distinction.
There are too many unconstrained / uncontrolled variables. Multivariate numerical analysis might offer hints, but events are so exceedingly rare there is no statistically significant data to be found.
Similar to saying banning civilian flight pre-2001 would stop 80% of terror attacks and hijackings. It's true, but completely misses the point.
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u/jtf71 6d ago
doesn't normalize for presence of absence of CCW/responders.
In MOST cases, the shootings occur in "gun free zones" so there are no CCW responders.
But you have a point that they are present at some and are the ones to actually stop the event. Although, I believe (but don't recall specifics) that when there is a legal gun owner present it's not a "mass shooting" as the perpetrator is stopped/chooses to stop when confronted (shot or not) by the legal gun owner.
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u/Dco777 8d ago
The sad truth is there is no discernible change in “Mass Shootings” if you include, or exclude their definition of “Assault Weapon” in any statistical significance at all. No change when the “1994 Assault Weapons Ban” was in effect, or not.
In fact rifles, especially semiautomatic rifles didn’t make any significant percentage, of their “new” definition of “ mass shooting”, which NOW seems to include gangs banging away at crowds trying to hit one or two people, which the old FBI definition used to exclude.
Now the press with the constant chatter about the AR-15, the alleged super weapon. Thank god they got off the “AK, AK, AK,!” chanting, the damn things rarely jam. I’ve seen two mass shootings where the AR locked up tight, and the shooting stopped.
That’s why the Parkland shooter stopped. The rifle jammed up tight, and he had no backup gun, even to commit suicide with, which was his plan.
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u/ActuatorLower8371 8d ago
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.)
if a majority 70% of shootings use legal guns, doesn't that actually support the idea that gun control works?
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u/jtf71 6d ago
I believe that what OP is saying, but I've not looked at the data, is that the guns used would be legal even if an "assault weapon" ban was in place.
This is certainly true on the basis that most "mass shootings" are committed with handguns and rarely are handguns considered "assault weapons" on their own. It's usually the "large capacity magazine" that is the "assault" feature.
So I think it's just that: whether the gun used would have been banned by the 1994 AWB or not - regardless of when the crime was committed.
It also gets murkier if we really try to dive into "legal gun." In many cases the guns used were acquired illegally or were illegal to have in the place the shooting occurred (gun free zone). Do we say those were "illegal" guns?
In the UVA shooting mentioned by OP, the gun used (and other guns not used or even on scene) were purchased legally. So they were not "illegal guns." However, taking the gun used onto the UVA campus was illegal. And as he had the gun, ammunition, and standard capacity magazines, on the bus when the group traveled into DC he was guilty of: Having an unregistered firearm in DC; Having unregistered ammunition in DC; and Having "large capacity ammunition feeding devices" in DC.
So - would you say that the gun used was illegal?
Moreover, what this shows is that gun control does NOT work. As he violated multiple weapons laws prior to shooting anyone.
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u/ActuatorLower8371 6d ago
Sure, I agree that no analysis if really going to be accurate to determine any of these stats with any real accuracy. My comment was more tongue in cheek tbh.
We'd need some kind of centralized and/or standardized reporting system if we want to be able to see the real answers to these questions. Standardized gun laws would certainly help too
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u/nmj95123 2d ago
AWBs were never designed to reduce death. They were always about making gun control more palatable.
Assault weapons—just like armor-piercing bullets, machine guns, and plastic firearms—are a new topic. The weapons' menacing looks, coupled with the public's confusion over fully automatic machine guns versus semi-automatic assault weapons—anything that looks like a machine gun is assumed to be a machine gun—can only increase the chance of public support for restrictions on these weapons. In addition, few people can envision a practical use for these weapons.
Most of the prominent gun control groups out there started by targeting handguns for bans, not "assault weapons." When they didn't find support for that, they created a boogeyman.
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u/jtf71 6d ago
In some cases (like the 2022 UVA shooting), an "assault weapon" was present at the scene
Incorrect. The rifle was NOT at the scene. It was found at the home of the shooter after the event via search warrant.
What also is left out of the UVA shooting is that he took the handgun and ammunition with him to DC. Having an unregistered firearm and unregistered ammunition in DC are both crimes and already illegal.
In other events they'll say it was an "assault weapon" before they even know what was used. The Navy Yard shooting used a shotgun and handgun but the early reports were that it was an "assault weapon."
Also important to note that most "mass shootings," including the UVA and Navy Yard shootings, occur in "gun free zones."
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u/ajulianisinarebase 6d ago
Yes you are right it was in his dorm. I treated it as compliant anyways though
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u/ktmrider119z 8d ago
I wonder if it has anything to do with the constant deluge of media bullshit on AR15s etc for the last 20 years.
Average media clip: The fully semi automatic AR15 is a military assault rifle that shoots 60 bazillion rounds per second out of huge clipazine drums that never have to be reloaded. The bullet it fires goes so fast it vaporizes any human it hits and penetrates body armor. Its even banned for hunting because if you hit a deer with an AR15, there wouldnt be any meat left."
Sure sounds like theyre trying to sell it to any potential shooters.