After Las Vegas, it’s nice to see that some Republicans are willing to consider banning bump stocks, the devices Stephen Paddock apparently used to make a dozen semi-automatic assault weapons mimic the firing rate of a fully automatic machine gun. Several top Republican senators and House members who (it goes without saying) are normally opposed to anything resembling gun control have said they are open to the possibility. Even the NRA says it supports additional restrictions on the devices. But that’s not nearly enough.

Bump stocks are modifications to guns like the AR-15 and AK-47-style weapons Paddock used that take advantage of a rifle’s recoil to allow a shooter to pull the trigger far faster than a human could ordinarily do. The shooter pushes forward with his non-trigger hand (usually on some kind of forward grip), and the bucking of the weapon against his shoulder causes his finger to depress the trigger multiple times per second. That would be useless in hunting, self-defense or target shooting because it makes the weapon hard to control and nearly impossible to aim. About the only thing it’s good for is firing indiscriminately into a crowd. We should absolutely ban them and similar devices, like trigger cranks, which achieve a similar effect.

But we would be kidding ourselves if we believed that would have prevented something like the Las Vegas killings. It is not just the modification to Paddock’s assault weapons that made them so deadly but the nature of the guns themselves.

Gun advocates like to claim that that weapons like those Paddock used are only cosmetically different from hunting rifles and no more deadly than semi-automatic handguns. But this particular mass shooting demonstrates how false that is.

Handguns can fire a shot with each pull of the trigger, just like an assault rifle, but they typically only have an effective range of about 55 yards. Paddock fired from a perch about 320 feet above ground and about 400 yards away from the concert crowd. Only a rifle could have hit a target at that distance with any kind of accuracy. But a hunting rifle typically requires the shooter to pull back a bolt to chamber a new round after each shot, which greatly limits the rate of fire.

Hunting rifles also don’t usually have detachable magazines, as assault weapons and semi-automatic handguns do. Paddock reportedly had large-capacity magazines, meaning he would not even have to change those frequently. Rapid fire, even without a bump stock, can quickly cause a gun’s barrel to become so hot that it would burn the shooter’s hand. Assault weapons tend to have barrel shrouds or forward pistol grips to solve that problem. Rear pistol grips or thumbholes in the stock also help the shooter control the weapon during rapid firing.

We don’t yet know all the details of the arsenal Paddock had in his hotel room, but one other common feature of assault weapons would make an attack like the one he perpetrated more difficult to stop. Assault weapons often are designed to accept flash suppressors, which both help prevent the shooter from being blinded by muzzle flash during rapid firing and make it harder for others to detect his position. Police reportedly found Paddock not because they could see exactly where the shots were coming from but because the gunsmoke in his room set off the fire alarm.

Finally, the death toll and the severity of injuries was so high not just because of the number of bullets Paddock was able to fire but because of their effects on victims’ bodies. Weapons like the AR-15 have a muzzle velocity about three times that of handguns, meaning the bullets strike with substantially more force. After the Pulse nightclub shooting, Wired magazine interviewed trauma surgeons about the difference between wounds caused by handguns and by assault rifles. The former typically cause relatively simple, knife-like wounds. The latter crush bones, pulverize organs and send ripples of trauma throughout the body.

By all means, yes, we should outlaw bump stocks. But this mass shooting is a textbook case for why we need to ban assault weapons, too.