Right to Keep and Bear Arms is a DKos group of second amendment supporters who 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 or somewhere in between, 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.  
On Daily Kos, I keep seeing terms like “high powered,” “hollow point” and “high capacity” thrown around. Some of these are terms of art, others are just misused and misunderstood. Without some understanding of these technical issues, we do not have a foundation to discuss any policy implications.

Ammunition is what a gun fires. To keep this simple, I will only discuss the metallic cartridge because its the most common form of ammunition today. Ammunition has four components, the case, bullet, propellent, and primer. The case is typically made from brass but can also be made from steel, copper, or aluminum. Some efforts have been made to produce plastic cased ammunition but these have not been commercially successful. The case serves to seal or obturate the breach, hold the cartridge's components together and when ejected helps to cool the gun. An early breach loading rifle called the Dreyse needle-gun used a paper cartridge and did not seal the breach very well causing soldiers to commonly singe their eyebrows off. The bullet is what the gun fires, it is commonly a lead core wrapped in a copper or a copper alloy jacket. The propellent is commonly smokeless powder, or in some loadings for old guns, black powder. Many people use cordite as a synonym for smokeless powder but its just a variety used by the British in the .303 military ammunition. Finally there is the primer which ignites the power charge when subjected to a sharp, mechanically delivered blow. Primers used to be made from mercury but today are made from less toxic compounds. Old primers are known as corrosive and deposited hygroscopic salts (these salts absorb water and cause rusting) on the bolt head, bolt assembly, firing pin and in the bore that had to be removed, typically via chemical neutralization. They show up for sale in some lots of surplus Russian and Communist Bloc Ammunition from as late as the '80s. Rimfire cartridges locate their primer in the cartridge rim and the rim is struck by a firing pin. Center fire ammunition can handle higher pressures and locates the primer in the center of the base of the cartridge. The base of the cartridge is head-stamped to provide information on the manufacturer or factory, year of production or date code and ammunition type for quality control and identification purposes.

Shotgun ammunition differs in that the base of the cartridge is brass and the hull is typically polymer. It typically holds either a single projectile called a slug or multiple projectiles called shot. Smaller shot is for birds and trap/skeet shooting. Larger shot is used for deer and self defense. Shotguns are close range weapons because their shot spreads about 1” per 3' traveled, typically loosing effectiveness at 40-50 yards. Slugs are effective to about 100 yards because of their low velocity and aerodynamically poor shape.

Bullets come in many shapes and sizes. They all must be able to seal the against bore to use the propellent effectively, this is either with a concave base that the pressure of burning powder pushes into the rifling or by being slightly larger than the diameter of the rifling. Bullets for hunting and self defense typically either have a hollow point or expose their lead core at the nose to encourage deformation on impact, increasing the effective diameter and effectiveness of the bullet. Many long range shooters prefer bullets where the jacket is drawn from the rear, leaving a tiny gap in the nose of the bullet. These are more aerodynamic and are better at retaining velocity.

Bullets used by the US military conform to the Hauge Convention of 1899's ban on bullets that expand or flatten easily. As I understand it, the British discovered that unlike the .577/.450 Martini-Henry, their new. 303 British was less effective at stopping insurgents in various oversees colonies that understandably desired to run their own affairs. The British resolved the failure to stop issue by exposing the lead core of the bullet and causing the bullet on impact to mushroom. My understanding is that Imperial Germany attempted to produce similar ammunition but were unable to get it to function correctly in their Maxim guns so they managed to ban the use of expanding ammunition between the parties to the treaty. The UK developed a new .303 cartridge loaded with a bullet that contained a core containing a forward section of aluminum or sterilized wood pulp and an aft section of lead.. In flesh, these bullets tend to deform and produce more serious wounds. Likewise the US 5.56 NATO destabilizes in flesh at close range turning sideways and breaking apart. The Soviet 5.45x39 has an air gap in the nose that causes the bullet to also destabilize in flesh and flip over once or twice, producing a more serious wound than a .21 cal ice pick hole that would occur if the bullet passed straight though.

Wound ballistics (aka terminal ballistics), or what the bullet does in flesh has been studied various ways since the late 19th century.  Today bullets are fired into calibrated ballistic gelatin or a similar material and the permanent crush cavity recorded. Larger permanent cavities mean greater damage to flesh. There are other theories such as hydrostatic shock, temporary stretch cavities, the velocity kills ideology and Marshall & Sanow “one shot stops.” These do not conform to our understanding of terminal ballistics [PDF] and I will ignore them because it makes as much sense as discussing intelligent design.

Here are some YouTube videos of ballistic tests [Youtube]  (I do not endorse the videos or the presenter but am using them to illustrate my points) with my commentary. The key that I am discussing is the effectiveness of each bullet or in the case of shotguns shot or slugs. I am deliberately not discussing the legal framework here. The goal is to provide technical information to inform future policy discussions. Many of these videos make mention of the weight of the bullet in an old but still used measure of weight called grains. One grain equals 0.0648 grams.

Given that most murders are committed with handguns, lets start here. The least powerful commonly used cartridge is a .22 Long rifle and I have selected a few videos for discussion.

This video shows a .22 LR handgun and a .22 LR rifle being shot into ballistic gelatin. From the handgun the ammunition fails to expand and like most ammunition that does not expand, penetrates deeply. From the rifle the ammunition fails to penetrate as far because it expands and with more surface area slows down faster.

This test of 9mm defensive ammunition showed the comparisons of two commonly used defensive ammunition loads to standard 9mm ball ammunition. The two defensive loads are less likely to over-penetrate (that means they will tend to stay in whoever they were fired into and not endanger bystanders) and by expanding are more effective.

This test compares a modern M9 service pistol firing a 9mm (.355 inch) 115 gr FMJ bullet to a 1860 Army pistol firing a .451 cal ~140 grain spherical lead bullet. The .44 ball looks like it would be more effective as its of a larger diameter.

This video provides a comparison between the .380 Automatic Colt Pistol and the 9mm Parabellum cartridges from a self defensive perspective. Both are effective, the .380 less so because it has less kinetic energy.

The most common rifle in the US, that AR15 does have a reputation for being effective at close ranges. Many people were shocked at the effectiveness of the cartridges used by Adam Lanza but that's exactly what we should have expected. The M193/M855 and other service cartridges for the 5.56x45mm NATO tend to flip sideways and break apart in flesh at close ranges.  For instance when fired from the military M4, the maximum range where fragmentation will occur is about 100 meters.  The civilian 16inch rifles and 20 inch rifles drive the bullet faster so the effective fragmentation envelope is larger, slightly more than 100 and 150 meters respectively.  This does not mean that at 100 or 150 meters the bullet magically turns into a puff of smoke.  A well trained marksman can still  hit his target as far away as 600 meters.  As range increases, its terminal performance becomes more an more like a ice pick.

This video shows what military ball cartridges do in ballistic gel. Although its fairly high velocity, this example does not fragment.

This video shows another military load that although it impacts at a much lower velocity does fragment. Velocity does not make a bullet more deadly. Bullet construction matters more that its impact velocity. Some 5.56 ammunition such as the Swiss Gewehrpatrone 90, having an extra thick jacket, does not readily fragment. I can't find a good reference or pictures for this one though.

Remember the shooting in Chicago where 13 people were shot but thankfully none died? There was some questions on DKOS, so I found some videos showing the difference between various types of bullets loaded in the 7.62x39mm Soviet cartridge that is used commonly in the SKS and AK47 rifles.

Military FMJ

Russian Soft Point

US made Hollow point.  

The Military FMJ and the Russian Soft Point ammunition both did not expand and punched straight through the gel block. The Hornaday hollow point did expand as predicted. Thankfully the shooters in Chicago most likely used cheap FMJ ammunition and no one died.

Other civilian cartridges are also very effective.  For instance the classic deer hunter's cartridge the .30-30 soft point has a reputation for being very effective against people as well as deer. Its an old cartridge that has a bit more kinetic energy than the 7.62 Soviet. I can't find a good video or picture showing its effectiveness however. Cartridges used in hunting medium sized game such as various hollow pointed and soft pointed .30-06 Springfield would be even more effective against humans.

Compare these to the effectiveness of a shotgun:

No need to go into great detail. Shotguns loaded with buckshot, buck/slug or slugs are very effective at stopping people.  #4 Buck shot tends to stay in the victim while heavier 00 and 000 tend to exit their body.  A slug will almost certainly exit.

Lastly, there is some confusion on the role of magazine capacity. That belongs in another article so I will keep it simple. For handguns, larger diameter bullets mean fewer but more effective cartridges per magazine. Standard capacity magazines are what the gun is designed to use. Deviating from using these produces a chance that the magazine will not feed properly. For example, I have a SIG P6. Its factory magazine holds 8 cartridges. There are aftermarket magazines that hold 10 cartridges but these have a poor reputation and are known to make an otherwise reliable handgun mis-feed and jam. Likewise, the most reliable magazine for the AR15 holds either 20 or 30 cartridges because that what the military has tested and resolved most issues. AK rifles have a standard magazine that hold 20 (there are a few rare Hungarian made magazines in the US) or 30 cartridges. Some aftermarket magazines are known for causing feed failures and stoppages. Well designed and properly manufactured magazines intended to contain more than the standard number of cartridges get expensive quickly.  Even then they often are not as reliable.  

Note: The gun being used in the test is an NFA regulated firearm that costs about $15,000 and requires a long wait for a very though background check to purchase.

In usage, most gun owners use less expensive FMJ ammunition for target shooting. Ammunition for hunting and self defense is designed to expand or less often, fragment so that it does not endanger bystanders and is more likely to cleanly kill the game animal or stop the human attacker.

From a policy perspective, handguns are less effective than long arms at hurting people. Rifles are less effective than shotguns. However, most gun control efforts today seem to be predicated on making it impossible to buy otherwise popular long arms (such as in my State, Maryland) and severely restrict the ability to legally buy handguns. None of which are as effective as shotguns for stopping humans.

I hope that this will provide some assistance in discussing gun ownership by providing technical background.

Edit:  Correct a minor spelling mistake.  

Originally posted to DavidMS on Sun Dec 01, 2013 at 08:30 AM PST.

Also republished by Right to Keep and Bear Arms.

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