Getting down to basics

Before anyone can pick up and discharge a firearm responsibly, first they must study and comprehend what it is exactly that they are doing from a mechanical and physical sense. When discharging a firearm you are setting off a complex chain of events that must be understood. There are many carefully calculated events taking place each time a round is fired. If strict guidelines are not adhered to, safety issues arise and injuries may occur. Without a clear understanding of the mechanics and physics involved, it is not a good idea for a person to handle much less discharge a firearm.

In general a firearms cartridge is comprised of four parts. The most obvious and prominent of the four are the casing and projectile. The other two parts are the power and primer. When these four components are assembled into what’s referred to as a cartridge, they represent an integral unit that works together with the firearm as a system by which a projectile can be expelled down range towards a target under controlled circumstances.

There are of course many different designs of firearms, cartridges and projectiles however they all operate under the same conditions with few minor exceptions.

We will begin with a basic analysis of the cartridge, using a typical brass rifle cartridge. To begin with the brass case is the component of the cartridge in which the other three components can be found. The precisely measured power charge is contained within the case, the primer (the “detonator” or component that ignites the power charge) is found in a recessed pocket flush with the bottom of the case and the projectile (also known as the bullet) is inserted into the top or “mouth” of the case. The projectile is held in place by the tension of the opening of the mouth being slightly smaller in diameter and the projectile it is holding. The firearm in which the cartridge will be utilized typically has three major components: a stock, barrel and receiver. The type of receiver and manner by which cartridges are fed into the chamber are what makes up the type of action a particular firearm is identified as.

In the end of the barrel that is mated to the receiver is drilled out in almost precisely the same dimensions as the outside of the cartridge. This end of the barrel where the cartridge will be inserted is known as the chamber. The chamber is drilled out slightly larger than the cartridge enough to allow easy insertion and removal of the cartridge.

When the shooter it’s ready to discharge the firearm a cartridge is inserted into the chamber and the action is closed behind it. Upon pulling the trigger a spring forces a hammer to strike a firing pin which then strikes the primer in the bottom of the cartridge setting off its detonating charge which in turn ignites the powder which burns at a specific and calculated rate. When the powder burns it produces hot expanding gasses which exert extremely high pressures within the case forcing it to swell outward against the inside of the chamber creating a tight seal between the outer wall of the case and the chamber wall. The only place that these continually expanding gases is forward against the bottom of the projectile which gets forced out of the mouth of the case and into the bore of the barrel. The remainder of the powder burns well down the barrel continuing to exert force against the projectile until it leaves the muzzle. By this time the projectile can be traveling at up to and in some cases faster than 3,000 feet per second. Sometimes when a firearm is discharged there is a visible orange flash seen at the muzzle. This is the result of powder that didn’t fully burn within the barrel burning in the air behind the escaping projectile along with the hot gases being ejected from the muzzle into the cooler outside air.

Immediately following the departure of the projectile and gases from the barrel, the pressure that was produced inside the case to move the projectile drops back to normal and the elasticity of the soft brass case allows it to relax away from the chamber walls. This allows for easy extraction of the casing but leaves it slightly enlarged than it was prior to firing. This process is known as “fire forming.” It requires that the case be processed by resizing dies if the shooter plans on reusing the brass for reloading purposes. If the case will be reused in the same firearm it need only be neck sized to reduce the stress on the brass. If the case will be used in a different firearm it will more than likely need to be full length sized as it may not fit inside the chamber of another firearm despite being the same caliber.

The process of reloading a case into another useable cartridge includes cleaning the empty case, removing the spent primer, resizing the brass back to it’s original specifications, inserting a new primer, charging with powder and installing another projectile.

This process can be repeated as many times as the integrity of the case to perform it’s job safely without splitting, cracking, separating, or showing other signs of unsafe stress.

Reloading should only be done by those with a full comprehensive understanding of the entire process and of what conditions each component of both the firearm and cartridge parts are exposed to during firing. It is not recommended that the average or novice shooter bother with reloading but rather sticks to using factory new ammunition each time to avoid possible injury or even death to themselves or others.

Once you have studied and understand all these processes involved with discharging a single round from a firearm, then you can begin to concentrate on becoming a safe and knowledgeable shooter.


MJ McGowan

.40 or .45?

Understanding how the .40 S&W is a better defense round than a .45 ACP takes a study in the dynamics of many physical properties. I always liken the comparison to asking someone which they’d rather hit with: a volley ball thrown at their chest at 30mph or a golf ball at 30mph?

This does in fact represent an exaggerated example, but the basics remain the same throughout. A typical 230 grain .45 ACP round will be moving at approximately 800 to 1000 feet per second at the muzzle while the typical 165 grain .40 S&W projectile will be traveling approximately 1000 to 1200 feet per second. Conventional wisdom dictates that despite the slower velocity of the .45 caliber projectile the difference in weight and kinetic energy gives the bigger round more knock down power. It’s the old “bigger is better” theory. However when we’re talking about a firearm’s ability to stop an aggressor from having the capacity to inflict harm upon others, old wives tales do not apply. Science and physical facts are the important indicators. When it comes to statistical data, there is no argument that in the 2 decades since it’s introduction the .40 cal has proven itself a formidable defensive option but overcoming the 10 decades and nearly 4 generations of testimonial usage of the venerable .45 make for an almost impossible task of convincing anyone that sometimes smaller is at least as good, if not better.

Having seen documented statistics of nearly all offerings of commercially available ammunition for both the .40 and .45 in bullet weights ranging from 135gr to 180gr in .40 and 180gr to 230gr in .45, and only looking specifically at the most commonly used weights for each respectively it was obvious and undeniable that the .40 cal could indeed meet and in some cases exceed the penetration of the .45 in ballistic gelatin. Also noted was the ability of the .40 to expand to a greater percentage of it’s original diameter and create a wound channel comparable to that of the slower moving .45 projectile which starts out larger, but slows more rapidly upon contact with a media and therefore does not inflict a greater amount of tissue damage as what many perceive based on the “bigger / better” school of thought.

The greater speed of the smaller diameter projectile reduces the snow plow effect of the big blunt frontal cross section of the .45 bullet upon impact and allows it to penetrate more deeply, yet expand predictably and uniformly to dispense it’s energy along the wound channel to incapacitate the target.

Now granted, if given the choice between which one I’d rather be shot with there is no sensible argument that you stand a better chance of surviving one over the other, ergo I would not want to be shot with either one. I would not want to be shot with a .17 caliber air rifle for that same matter as far as that goes. When choosing which one I would rather rely on to defend myself against an aggressor threatening my life or that of others, both are capable of getting the job done but one has slightly better inherent physical properties to get the job done with greater efficiency.

I won’t even throw in the arguments of less recoil, smaller easier to handle pistols and higher capacity capabilities. Those are all trivial in the bigger picture. Maintaining a concentration on actual target performance a 165gr .40 caliber hollow point bullet traveling at 1200 feet per second, penetrating up to 13 inches of gelatin and expanding up to 1.5 times it’s original diameter will reach and inflict greater incapacitating damage to a human subject than a 230gr .45 caliber round moving at 950 feet per second, penetrating 11 inches and expanding 1.25 times it original diameter.

Kind of like comparing the bruises you’d get on your chest from the volley ball and the golf ball.

Of course there are those who will point out emphatically that a .45 will consistently knock down bowling pins as compared to a .40 cal, and that’s a valid argument when talking about bowling pins. If I was confronted with by a bowling pin packing heat and threatening my life, I’d undoubtedly want a .45 to knock it down without question. But seeing as that I’m more likely to be confronted by a 6 foot sack of water, tissue, organs and bones than a 20 inch plastic encased block of hardwood, I’ll take the .40 S&W.

On a non scientific note, one must also look at time and technology. When the .45ACP round was developed, solid rubber tires on wooden rims were the state of the art in performance for automobiles. There is such a thing as “tried and true.” I won’t argue that. But in some cases the best service something that was developed decades ago can provide us with is the ability to study it and make improvements in successive designs.

That is solidly the case where the .40cal round is concerned. After all, before something can be “better than sliced bread” there must first be sliced bread. The .45 is a fine loaf of sliced bread. The .40 simply adds the “better than” part.

MJ McGowan