RKBA is a DKos group of second amendment supporters who also have progressive and liberal values. We don't think that being a liberal means one has to be anti-gun. Some of us are extreme in our second amendment views (no licensing, no restrictions on small arms) and some of us are more moderate (licensing, restrictions on small arms.) Moderate or extreme, we hold one common belief: more gun control equals lost elections. We don't want a repeat of 1994. We are an inclusive group: if you see the Second Amendment as safeguarding our right to keep and bear arms individually, then come join us in our conversation. If you are against the right to keep and bear arms, come join our conversation. We look forward to seeing you, as long as you engage in a civil discussion. RKBA stands for the Right to Keep and Bear Arms.
To kick off this occasional informational component to our usual RKBA series, let's talk about ballistics of common firearms.
First, some common terms and simple explanations of what they mean.
Ballistics is the science of moving projectiles.
Bullet is the actual projectile fired from a gun.
Caliber is the diameter of the barrel of a firearm.
Cartridge is the package which includes a case holding gunpowder, some means of ignition, and a bullet.
Why does this matter? A gun is a gun is a gun, right?
Well, no. There's a big difference in what guns are, how they work, and what they can do. For this diary I don't wish to get into a big discussion of the ways guns operate, but rather to focus in on the one thing all of them have in common: launching a bullet out of a barrel.
Why would this matter, when more people seem to argue over handguns versus long guns, or over semi-automatic guns versus automatic weapons? Well, because when it comes to determining public policy, it pays to know a little something about the matter you wish to regulate.
OK, let's look at that initial term: Ballistics. As relates to firearms, there are a lot of things about the motion of a projectile which one can study: the initial movement within a barrel; the flight outside of the barrel; and what happens when the projectile hits something. Generally speaking, the larger the bullet and the faster it moves, the more energy it has and the more damage it can do. That's basic physics. But the shape of the bullet also matters - the round balls used in muskets tend to lose their energy more quickly (due to friction with the air) than a cylindrical bullet does, and a bullet with a pointed end does even better. Likewise, playing games with different materials used in a bullet makes a difference both in how it effects movement and what happens when it hits something.
Keeping on with the discussion of bullets, they can be designed to do different things. A simple lead bullet (of modern shape and design) is great for just target shooting, but leaves some residue in your gun barrel, may present an environmental contamination problem, and generally isn't considered the best option for use in self defense. If you put a cavity at the front of the bullet, it may deform faster on impact, imparting more of its kinetic energy into the target and causing a wider (but shallower) hole in soft tissue. If you put a coating (or "jacket") of some other material around the lead bullet (copper is commonly used) it will stop the bullet from deforming so much and penetrate more deeply. Then there are 'Jacketed Soft Points' (JSP) and 'Jacketed Hollow Points' (JHP) which attempt to find a good balance between penetration and expansion. There are even bullets made entirely of materials other than lead, in the search for better performance and to limit environmental impact.
But what really matters more is the size/weight of the bullet, and how fast it is moving. The first factor in this is the diameter of the bullet, or caliber. Caliber is usually given either as a decimal fraction of an inch - .45 means that it is 45 hundredths of an inch across - or in millimeters - 9mm across. Sometimes these measurements are historical artifacts; for example a ".38 special" actually uses a bullet of .358 inch diameter. But caliber can only tell you so much, because there's a huge difference made by the weight and velocity of a bullet.
And that leads us to cartridge. Because there's a huge difference in how fast you can push a bullet of a given diameter, depending on how much gun powder is used and whether that powder is completely burned before the bullet leaves the barrel of a gun. If you look at the differences between handgun and rifle cartridges, you'll see the difference immediately: handgun cartridges are relatively short, usually straight-walled, whereas rifle cartridges are longer and often have a 'bottle' shape. Basically, handgun cartridges contain less powder, designed to be burned relatively fast, for a short burst of acceleration. And rifle cartridges hold a lot more powder, designed to burn for a longer period of time, for a longer period of acceleration resulting in a much (2x or 3x is typical) higher velocity of the bullet before it leaves the barrel.
There are ways to optimize all of these factors, but you can't cheat physics. To accelerate a large bullet needs a lot more energy, and that means both a larger cartridge and greater recoil - which has to be managed in some manner (mechanically and/or through inertia) or absorbed by the shooter. Likewise, if you want to push a bullet very fast, and do it in a very short time interval, you have to do it using very high pressures and there are functional limits to what materials will stand.
With rifles, you can make them incredibly powerful, but that usually means that they have to weigh a lot (or be mounted to something) in order to be manageable. With handguns, you're always making a trade-off between power and concealability, and a further trade off in terms of capacity and cost (exotic materials needed to withstand very high pressures and be lightweight are expensive).
I always have to laugh when I come across someone wanting to limit handguns to a certain capacity in an effort to limit how "dangerous" they are. First, swapping out magazines in a modern handgun takes an extremely short period of time (on the order of about two seconds for anyone who is experienced), and second, because the more rounds you have in a handgun to start with, the heavier it is and the more awkward it is to conceal it worth a damn.
What about restricting bullets in some manner, to make them less dangerous? Aren't there some types of Teflon-coated bullets designed to defeat protective vests - you know, the "cop killer" bullets? Well, no. There aren't. There never were - the "Black Talon" bullets were withdrawn from the market for a while due to PR problems, but were then re-introduced later under another name. And they're functionally no different than just about any other modern self-defense ammo.
How about so-called "assault rifles"? Aren't they more powerful and therefore more dangerous? Nope. Look up above about how I described the difference between a rifle and a handgun: it's the size of the cartridge and the length of the barrel. Most good hunting rifles are at least as powerful as any scary black rifle such as were covered by the AWB - they use larger cartridges, shoot heavier bullets at a higher velocity, and have a greater effective range. In fact, they're more likely to defeat a protective vest or penetrate some barrier. Again, it's the physics which matter.
And then there's shotguns . . . but that is probably a topic for another diary.
Jim Downey
(Here's why I know about some of this stuff: I'm one of the main people behind Ballistics By The Inch.)