Month: March 2018

Jargon: “Bullets” Are Components

Jargon: “Bullets” Are Components

A term that is certain to raise the hackles on shooting aficionados is to call ready-to-fire ammunition “bullets.” “Bullets” are components, and only one of the four components that comprise a complete cartridge, or round. As can be surmised from the opening lines, a complete, ready-to-fire ammunition component is called either a “cartridge,” or a “round.” Modern ammunition is found in one of two types: Centerfire and rimfire. Rimfire cartridges are most familiar as those shot in .22 caliber firearms. Although rimfire cartridges have all the components a centerfire cartridge have, we will concentrate on, and describe the components from a centerfire point of view, since centerfire components are more easily differentiated.

Primers

Primers are the ignition point in a cartridge. When looking at the back of a complete cartridge, the primer is the round component pressed into the center of the case (hence, the name “centerfire”). Primers are made with a pressure-sensitive compound that produces a spark when struck (compressed) by the handgun’s firing pin or hammer.

Case

The case is the metallic container that holds all the components in proximity to one another. It is usually made of brass, but may also be found as steel, aluminum, and in some instances, a polymer. The open end of the case is called the “mouth.” The end of the case where the primer is seated is called the “head.” Cases are made with several different head styles (called rims) mostly depending on the style of handgun for which they were designed. Rimmed, semi-rimmed, rimless, rebated rimless, and belted rimless are among those seen. Most revolvers use a rimmed case, and most semi-automatics use a rimless case, although there are exceptions for both handgun types. Rebated rimless, and belted rimless are most often seen in rifle calibers. Cases also differ in their contour. Most handgun cases are a straight wall design, meaning the diameter of the mouth and the diameter head are the same. Some cases have a reduced mouth, and the case widens to a larger diameter about 1/3 down the case. Often, these cases are referred to being “necked down.”

Powder

Powder (or propellant) is the combustible material held by the case, which when ignited by the primer produces sufficient gas pressure to force the projectile through the barrel. Smokeless powder is produced in numerous granule shapes, sizes, composition, and coatings to control the rate of combustion.

Bullet

Bullets are the projectiles forced out of the firearm by the propellant’s gas pressure, and are made in a variety of materials and shapes. So called “lead” bullets are actually alloys to increase the bullet’s hardness, and to reduce the deposition of metal deposits in the barrel and chamber, called “leading.” Other bullet compositions are jacketed and semi-jacketed. Jacketed bullets usually encase a lead core with a copper alloy or copper wash to reduce barrel leading. Semi-jacketed bullets have a partial jacket to reduce barrel leading, but leave some lead exposed to increase probability of bullet expansion upon striking its target. Recent developments in bullet technology see steel cores and solid copper bullets to achieve certain penetration or expansion goals.

The Total Package

Commercial ammunition is packaged with mostly prominent markings that identify the caliber, bullet style, and bullet weight, and, often, the average velocity. Thus, one sees packages marked, for example, “380 Auto 80gr DPX, Velocity 1050 fps”. Decoded, this is a .380 Auto (or .380 ACP), with an 80 grain DPX bullet, and a velocity of 1050 feet per second. Another example may be, “9mm Luger 124 Grain HST JHP”. Decoded, this is a 9mm Luger (also known as 9mm Parabellum, or 9x19mm), with a 124 grain HST, Jacketed Hollow Point bullet. In both instances, the letter designation (i.e., DPX and HST) is contrived by the manufacturer to identify proprietary bullet designs. One other bullet designation with which semi-automatic handgun users should be aware is “FMJ,” or Full Metal Jacket. In some instances, the user will have to be aware of alternative names by which your caliber is known. We have already seen that 9mm Luger may be labeled 9mm Parabellum, or 9x19mm. Another example is .45 Auto, which may be labeled .45 ACP.

A note of caution: modern firearms are marked prominently with their caliber. Always, USE ONLY THE EXACT CARTRIDGE CALIBER THAT CORRESPONDS TO THE MARKINGS ON THE FIREARM! Using a cartridge for which the pistol is not designed can result in serious injury or death.

Jargon: Handgun Actions-Single, Double & Beyond

Jargon: Handgun Actions-Single, Double & Beyond

Among the topics of conversation between pistol shooters is the topic of handgun actions, and which is best (as if there is a “best”). Neophytes take heart–action types are not difficult to understand, and the different action types presented below can be found in both revolvers and semi-automatic pistols, with perhaps one exception. As we begin the discussion of handgun actions, we start with the trigger press since it initiates the firing of the handgun. We also start with the trigger press since it best describes and differentiates the different types.

Single Action
In a single action handgun, the trigger press does one function and one function only–it releases a cocked hammer. Nearly everyone is familiar with the Hollywood image of a cowboy pulling a revolver from a holster, cocking the hammer, and pulling the trigger. That iconic handgun is a single action revolver.

Replica 1860 single action Colt revolver
Modern single action revolver

Improvements in internal safety mechanisms did little to change the profile of the classic single action revolver. The trigger press simply releases the hammer.

Single action, however, is not limited to revolvers:

1911 Semi-automatic pistol

The 1911-style semi-automatic pistol is a classic example of a single action handgun. One again, the sole function of the trigger press is to release the hammer.

Double Action
In a double action handgun, the trigger press does two things: It cocks the hammer, and then releases it to fire the handgun.

Modern double action revolver

This graphic demonstrates what happens internally to actuate and release the hammer.

Striker Fired
Arguably, the third unique type of handgun action is striker fired. Handgun aficionados debate whether the striker fire is a unique type, or merely a derivation of the double action. Depending on a manufacturer’s design, the striker (firing pin) is partially cocked, the trigger press merely completes the rearward movement of the partially cocked firing pin, and releases it, firing the handgun. In other designs, the striker (firing pin) is fully cocked, and the trigger press simply releases it.

Modern striker fired handgun

This graphic demonstrates the internal function of a striker fire handgun. In some models, the recoil action fully cocks the firing pin, while it other models it does so partially, only.

And Beyond. . .
Handguns also can incorporate both double action and single action. Most double action revolvers are capable of single action as well, where the hammer is cocked manually, and then the trigger press simply releases it.Some semi-automatic handguns also combine double and single action. When the hammer is decocked (i.e., in the down position), the first trigger press cocks the hammer and releases it. The semi-automatic function of the handgun re-cocks the hammer, at which time the trigger press simply releases it to fire the handgun. Most double action/single action semi-automatic handguns employ a decocker that lowers the hammer to the down position, while at the same time blocking the firing pin to prevent the handgun from firing.

Double action, single action semi-automatic, decocked

This example shows a double action/single action semi-automatic in a decocked condition with the safety on. Note the position of the safety lever on the slide, just forward of the rear sights, and the position of the trigger.

The photo on the right shows the same handgun in a decocked

Double action, single action semi-automatic ready to fire

condition with the safety off. Again, note the position of the safety lever and trigger. This handgun is ready for a trigger press.

 

In the photo, below the handgun is cocked and ready to fire. Once again, note the position of the trigger, and compare it to the photos above and right. When the safety is moved to the safe position, an internal firing pin block actuates, and the hammer is released to the decocked (down) position.

Double action, single action semi-automatic handgun in single action mode

One notes from this post that handgun actions are not limited to a specific type of handgun. Revolvers can be both single and double action, and semi-automatic handguns can be both double and single action.

 

Magazines
Most semi-automatic (that is, self-feeding) pistols are fed from detachable magazines (please, do not call them “clips”). Magazines are simply box-like accessories that hold the firearm’s rounds under spring tension. The cycling of the pistol’s action extracts and ejects the fired case, and strips a new round from the magazine to feed it into the chamber for firing. Pistol magazines come in two flavors: single and double stack. In the single stack magazine, rounds are loaded directly on top of one another in a single column. Double stack magazines, on the other hand, stagger the column of rounds. Staggering allows more rounds to be retained per fixed magazine length.

This photo shows a double stack magazine on the left, and a single stack magazine on the right. Both magazines are essentially the same length. However, in this example, the double stack magazine holds 15 rounds, while the single stack magazine holds 7 rounds, only.

Jargon: “AR”–What It Means

Jargon: “AR”–What It Means

Recent events have escalated modern sporting rifles into the national spotlight once again. Although the focus of LNPDSA is pistol training, there is a need to dispel very common misconceptions about the “AR” designation of modern sporting rifles.

ArmaLite

To begin, “AR” is the designation the ArmaLite division of Fairchild Engine and Airplane Corporation gave to its rifle line, which began with a modest, bolt action .22 caliber rifle (AR-5) that could be easily taken apart and carried. Its first big brother was the AR-10, a rifle originally designed to compete head-to-head with the current U. S. military service rifle, the M14. The AR-15 was developed after the AR-10 to chamber a round smaller than the then current 7.62 x 51 mm NATO cartridge.

Stock Design

Before we go any farther, let’s take a look at rifle stock design. Typically, rifle stocks were designed to place the rifle’s barrel in the same plane as, and in line with, the shooter’s eye when the stock was placed in the shooter’s shoulder. The rifles of the late ’50s and early ’60s were no different.

veteranarms.com
Revolutionary War Musket
“Kentucky” flintlock rifle
funnyjunk.com
M1 stock grip and barrel alignment

The AR-10 was a radical departure from the typical design; its barrel and shoulder stock were in line. With the barrel and stock in line with the other, recoil impulse is directed straight into the shoulder. In the typical design, the lowered stock forms a pivot point about which the rifle rotates from the recoil impulse.

rockislandauction.com
AR-10

However, with a straight-line stock and barrel,  shooting-hand placement becomes an issue, thus the pistol grip. The stock, by virtue of the rifle’s design, became a two-piece arrangement; one behind (the stock) and one in front (the hand-guard) of the action. The straight-line stock and barrel also inhibit a conventional, manual bolt arrangement.

spartacus-educational.com
Bolt action

The Fire Selector

So, what differentiates an “assault rifle” (more properly called a military service rifle) from a modern sporting rifle? In a clause, selective fire.

guns.com
Fire selector on an automatic rifle

The image on the left shows the safety mechanism of an automatic rifle, where the selections are clearly marked “SAFE,” “FIRE,” and “AUTO.” In the “SAFE” position, the fire selector mechanically prevents the fire control mechanism from releasing the hammer. In the “FIRE” position, the fire selector mechanically limits firing to one round (cartridge) with each trigger pull. In other words, to fire a round, the trigger must be pulled, and then released before another round can be fired (semi-automatic fire). In the “AUTO” position, the fire selector limitations are withdrawn, and the rifle can fire multiple rounds with each trigger pull (automatic fire). In the image below, the safety mechanism lacks the “AUTO” selection. NOTE, however, that the absence of “AUTO,” alone, does not make this second rifle incapable of selective fire; there are also internal changes to the action that render the rifle mechanically unable to produce automatic fire.

Fire selector on a semi-automatic rifle

So, back to the original discussion. “AR” is an abbreviation for a rifle design from the Armalite division of Fairchild. It is NOT an abbreviation for “automatic rifle.” It is NOT an abbreviation for “assault rifle.” Furthermore, according to the Civilian Marksmanship Program, the AR-15 isn’t even a “service rifle,” but simply a semi-automatic first cousin. “AR” is simply part of the model designation of designs inaugurated by Armalite, just as Model 700 BDL is the designation for certain Remington rifles, the Model 70 is the designation for certain Winchester rifle designs, and the M&P 15 is the designation for certain Smith & Wesson rifle designs.