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ОглавлениеChapter 2 SHOTSHELL COMPONENTS
All types of shotshells are essentially the same, and all are very different, in the same way that all cars are the same, but none are identical. Shells have the same basic elements and those elements have basic functions. Nevertheless, there is a practically endless combination of these elements and reloading just one of every possible combination would be a lifetime of work.
Besides the tools needed to put them together, you need five essential ingredients to build a shotshell and we will discuss three of them – hull, primer and wad – in this chapter. (The shot and the powder, or propellant, will be discussed separately.) A shell consists of:
Check every hull before setting it in the resizing collar of your reloader. Scott Richardson inspects a bucket of .410-bore hulls before selecting those that are good enough to be shot once again.
• a hull or case, which acts as a container;
• a primer in the base of the hull, which the hammer strikes and causes to explode, thereby igniting the powder burn;
• a small volume of powder that burns rapidly and turns to a large volume of hot gas to push the shot through the barrel;
• a wad and/or shotcup to hold your pellets and protect them from the powder burn;
• and shot to fill the cup and shell.
In addition, a specific load may or may not have additional internal spacers to help fill the hull and balance the load.
One of the important factors of handloading is that because these elements, at first glance, seem so similar, you must study them carefully. Small differences definitely exist and both manufacturers and other reloaders testify to this fact. Keeping your reloading components separate, labeled and identifiable is a matter of preservation of life and limb.
Experienced handloaders recommend that once you find recipes that suit your shooting, stick with known components. Otherwise, there is a significant chance of confusing the materials, and in handloading that can cause a drop in performance and very unfortunate results.
THE SHOTSHELL HULL
The hull’s duty seems obvious, but in fact the hull has quite a few functions and all of them must perform precisely as designed to deliver quality shooting.
Certainly, the primary function of the hull is to package the powder and shell in a neat, sweet and complete unit. Since relatively few shotgunners are black powder enthusiasts, most of us just want to shove a shell inside the chamber, or in the magazine of our semi-automatic, and pull the trigger. We do not want to assume that the shell is anything other than okay. Period. When we are in the field or at the range, we want to pull the trigger, a lot, and worrying about rain or spilling powder and shot and waiting while the smoke clears and our buddies pour and ram does not sound like a real good day. Today’s shell provides convenience, safety and, with a few exceptions, the ability to recycle.
All wads are not the same. Certainly, they vary by gauge, but they also vary by load. A WAA wad is different than a Windjammer is different than a BP STS. Until you have a lot of experience reloading, follow your recipe precisely and even then, switch components with extreme caution.
All hulls are not alike. In the discount marts, you will find numerous boxes of low priced shells, often called promotional loads. These lead-filled shells are excellent for one-time use, but should not be considered seriously for reloading – okay, maybe once or twice, but with caution! There has to be a reason these shells are cheap. First, they are usually constructed with paper inserts inside at the base of the hull, and these inserts will soon detach and they can lodge in the gun barrel. Anything lodged inside your barrel is going to be a problem. Moreover, although over/under and side-by-side shooters secretly think of themselves as a notch above gas gunners, it is still the rare double barrel operator who conscientiously checks his or her barrels before inserting another two rounds and snapping the breech shut.
Hulls evolved significantly during the last century. Originally, the self-contained shotshell hull was brass from top to bottom. All-brass shells were cumbersome and expensive, however, and except for the base (sometimes called the head), paper rather quickly replaced the all-brass hull. A rigid brass base was retained to seat the base wad, hold the primer, contain the shaped paper hull and to provide a solid grip for the gun’s extractors after firing.
During the ‘60s, a remarkable development in shotshells took place, the introduction of plastic cases. Today, almost all cases are plastic, which is much easier and less expensive to form into a shotshell case than paper. Plastic hulls offer greater water resistance than paper and they truly are more pliable. The synthetic material also maintains a superior memory for crimps without the fraying associated with the edges of layered paper hulls. Plastic used for hulls is more resistant to heat than paper hulls, too, and is stronger for the amount of material required.
You can easily measure the precision of hulls and reloaded shells with a shotshell checker. Precision machined holes, labeled GO and NO GO, in this stainless MEC plate test for size and roundness.
Nevertheless, there is considerable pressure from outside the industry to shoot biodegradable components. (In my hometown in Florida, a city known for its liberal politics, the new “Gainesville Target Range” requires that shotgunners pick up not only their hulls, but their wads as well.) This trend may eventually mean that our ballistics tables include data on tomato skin shotshells and distinguish between Red Delicious apple seed pellets (#6) and Autumn Gold pumpkin seed pellets (#00 buckshot).
Manufacturers are developing more eco-friendly products and you will increasingly find them available as reload components. Kent/Gamebore recently developed a “photodegradable” wad, for instance; it is still plastic, but it incorporates properties that cause “accelerated breakdown.” Their Gamebore line has a 2-3/4-inch biodegradable varnished paper shell and a fiber shotcup. Kent’s Impact non-toxic shot is a tungsten matrix, which Kent says, flies “just like lead, only it is non-toxic.” This movement may, sooner or later, affect handloading in a giant way (It changed home photo developing enormously. Chemicals we used to simply pour down the drain are now known to be highly toxic!), but for the present, many options are available in plastic wads and shotshells.
Proper shell resizing is important with today’s close gun tolerances. The Super Sizer from MEC is a heavy-duty shell-sizer that is built-in to all new generation MEC presses.
At the base of the shell is the brass cup that stabilizes the hull and other components. Curiously, this “brass” cup is often not brass at all, but a lightweight steel alloy that is colored to look like brass.
Shotgunners obviously prefer that their shell bases look like brass, though. Why this is so would involve some cultural analysis, but a few years ago, the now-defunct shotshell manufacturer Activ tried aggressively to market a no-brass plastic case. This case was entirely functional and suitable for reloading as well. It incorporated a small metal ring molded into the base to grip the primer. Nevertheless, sales results were not pretty. Perhaps Activ’s hulls were perceived to be as not as strong as shells with visible metal bases, but from all reports, they were, and they did not require resizing in a reloading press, either.
When I bought my first shotgun, about 25 years ago, I learned that there were two kinds of shells, high base and low base. This referred to the height of the brass base. It was generally understood that low base equated with low power and high base with high power. Consequently, my buddies and I purchased high base shells for pheasants and waterfowl, and low base for grouse and woodcock. What a surprise it was to learn that there is no essential relationship between the height of the base and the power of the load! But myths die hard, so today we still have high-brass magnum loads and low-brass dove loads.
The height of the brass base on a shotshell is not an indicator of its contents or power. A high base shell does not necessarily contain a heavier load or greater charge of powder than a low base shell.
The metal visible up the side of the hull is designed to stiffen the shell, to give the extractors a firm shelf to grip and, especially with paper hulls, to provide a firm base of support for the load’s components. During the first half of the twentieth century, the size of the brass on a shell varied as manufacturers experimented with new paper and plastic hulls, new base wad materials and heights, new progressive powders and various configurations for consolidating the elements of particular loads. A sneaky difficulty with new hull materials was finding combinations that would best contain gas pressure from the burning powder without leakage around the seal or the base wad.
Today’s hull makers vary the height of the brass for the same reason that they use differently colored hulls. Different sizes help them and their customers distinguish between different types and sizes of shells in their line.
A sturdier hull base, one wrapped in metal, albeit lightweight and relatively soft as metals go, may have advantages when shot through gas-guns and pump-actions which tend to extract shells with greater force than over/unders or side-by-sides. For gas and pump guns, you need a shell rim to be made of a reasonably strong material and firmly attached.
Ray “Hap” Fling, a former All American Trap shooter from Ohio who now lives in Gainesville, Florida occasionally shot trap with the inventor of the plastic wad/shotcup in the ‘50s. The original, red plastic wad is marked “Pat. Pend.” on the powder side. On the shot side, it has an interior, six-pointed star-shaped structure, perhaps to help offset the shock of setback on lead pellets. The 12-gauge wad has four petals and measures 1-1/2 inches long.
There are two fundamental designs of plastic hull in use today: a two-piece, straight-sided hull and a one-piece, injection-molded, compression-formed hull. The straight hull has a removable base wad of paper or plastic that separates the powder from the metal of the base. This shell is typically the thinner of the two designs and is frequently the hull of choice for building powerful hunting loads where every micromillimeter is packed with powder and shot. PMC offers a straight-wall hull in its HP Competition load, however. These high-end target shells have a six-star fold and the hard shot contains 5-percent antimony.
The injection-molded or compression-formed hull uses an integral base wad, which is the wall itself tapering to the bottom toward the primer hole so that the thickening curvature of the hull itself is what separates the powder from the base metal. Winchester’s popular AA hulls are a good example of the more common compression-formed tapered hull. (They show a cut-away of the loaded hull in some of their recent advertising.) Typically, the thicker, injection-molded shells are the choice of hull for competition loads.
At the base of a straight-sided hull is the interior base wad. It is somewhat rare that this is a loose paper wad as in days past. Subjected to the intense flash of heat when the primer explodes and ignites the powder, a paper base wad can easily detach and fall out, deteriorate or blow into and stick inside the barrel. Reloading a hull without inspecting the fiber (or plastic, for that matter) base for adhesion is careless and unacceptable.
Today, many of these base wads are plastic and look like washers. Their functions are to separate the powder from the base, to elevate the powder to the top of the primer and to help seal the bottom of the shell. You do not want a gas leak anywhere, but it can be especially disturbing around the base of the hull.
By varying the thickness of the plastic base wad, a huge variety of load combinations is possible without mandating extreme measures in component adjustments. Instead of adjusting component height, ammunition manufacturers logically utilize various thickness base wads to facilitate many different load types. This allows them to get by with few part changes in the hull’s construction.
At the opposite end of the hull from the base is the crimp and no matter whether the hull is paper or plastic it needs to be positively crimped. One purpose of the crimp is to seal the end of the shell to prevent the shot from falling out and keep dirt from entering. The crimp holds everything in order inside the hull. It also keeps the powder and shot properly packed for that micro-second when the primer ignites the powder and pressure begins to build. The crimp is a patterned fold and it is essential for proper powder ignition and controlling the burn rate. Varying the depth of the crimp or otherwise changing a pre-established fold can quickly and surprisingly affect the pressure.
Beautiful, 6-fold factory crimps on Federal #6 12-gauge and #6 20-gauge shells, and a Wolf #8 12-gauge. You can build crimps just as good looking and, indeed, to be effective you must make this part of the reloading exercise a priority.
On many ranges, the rule is that if a shell hits the ground, it belongs to the range … and you can purchase your own shells from the club. This odd rule makes it tough on reloaders who shoot semi-automatics and pump guns, especially pumps like the Ithaca Model 37 High Grade that ejects hot shells straight down from the chamber, rather than out to the right or left side. For clay shooting, a double-barrel over/under with ejectors modified to hand extract shells might be easier on the back and give you cleaner shells to reload.
A few years ago, two types of crimps were common, the roll crimp and the star fold. The roll crimp dates from black powder days. Black powder was bulky, at least compared to today’s progressive powders, and it needed all the room it could get inside a shell. Everything was packed in tightly and a small over-shot card (also called a wad) topped off a roll-crimped load. The crimp rolled the hull firmly back on itself and down to the card, thus holding the powder and shot in place.
With the advent of more efficient smokeless powders, less length of hull was needed to contain the powder because less powder volume could accomplish the same or better results than black powder. Therefore, more hull was available for sealing the shell. The over-shot card could be dispensed with and the final quarter-inch of standardized paper or plastic shells was simply folded over toward the middle. Today’s final crimp depth is about 1/16-inch with either a six- or an eight-segment fold. Hevi-Shot shells were originally marketed with a roll-crimp, but with Remington’s partnership they have since switched to the more conventional eight-fold.
Is there a difference between the six- and eight-segment folds? Except for the number of leaves or folds, no, but it is believed that the eight-segment fold holds a little tighter and is therefore a little better for smaller shot, #7-1/2, #8 and #9 in target and small game loads. There is a tendency for the six-fold to be used with larger shot in hunting and field loads. The small shells used in the 28-gauge and the 410 use a six-fold. Although it seems counter-intuitive, the large shells of a 10-gauge also use a six-fold crimp, perhaps because they are heavy hunting loads.
The memory of a former crimp is not embedded in the plastic of a new hull, so it must develop a memory. Working this hull carefully into the crimp starter of your reloading press several times will introduce folds properly into the material. Often during handloading, you will be tempted to only tap the new hull into the crimp starter and move through this station rapidly. This is the wrong approach because crimp starting is vitally important to effective shooting. Impatient handloaders, after finishing such a load, occasionally discover that the closure in the center of the hull mouth is incomplete and that they have left a hole in the center where the crimp does not meet. Pellets can dribble out and this renders the ugly load functionally useless. This is a result of rushing through the crimping process.
Many experienced reloaders recommend that when you work with a new hull, consider using a six-point fold starter rather than an eight-point if you have a choice. The six-fold is easier to work and usually realigns easier.
INSPECT EVERY HULL
Because hulls are so important to successful shooting, you must inspect them carefully before you begin reloading. Sorting and inspecting hulls while you are sitting at the reloading bench can seem unnecessarily tedious, though: you are perched in front of your machine with your components and the power is on, but before you can load a single hull, you have to check the type, its integrity and cleanliness every time you set one up. Perhaps the best time to sort and inspect is while you are watching television. A golf, baseball or football game on the tube where action is intermittent, gives you the time and opportunity to check each shell. Then, when you sit down at your reloading bench, you can confidently pound out the reloads.
Initial sorting separates gauges and lengths. After that, you can sort for brand and type. Just because you are holding a 12-gauge hull does not mean that you can load it with just any 12-gauge recipe. Seemingly small but ballistically significant differences in hull material, design, capacity and wear affect loads profoundly.
Only factory loads are approved for competition at the highest levels, such as the FITASC World Championships. (FITASC is the international organization that governs sporting competition.) For utmost shooting consistency, reloaders will want to find a commercial load that is most comparable to the load they are pressing. Of course, if and when you reach the very highest levels of competition, gun and ammo manufacturers will stand in line to sponsor your shooting … and your reloading press will begin to gather dust.
Winchester advertises that its AA hull will “become the new benchmark of reloadability.” In the same ad, the Illinois company suggests that you can achieve at least 15 reloads from a single shell. Fifteen is a lot of reloading. Not only is the hull subjected to violent extremes of heat and pressure, but also the crimp must fold and hold precisely all of those times. One of the biggest problems in reloading is forcing yourself to discard hulls that may not be in the best shape. Winchester AA hulls have an excellent reputation among reloaders.
Nothing is going to work better for you – either in your reloading press or in your shotgun – than perfect shells. Many writers recommend that you begin reloading with a bag of new or even once-fired and pre-sorted shells that can be purchased from your local dealer or via a known internet vendor like Cabela’s. Unfortunately, it is well known that most shotshell reloaders use hulls well past their prime and wind up trading performance for economy. No one would consciously choose to make this trade, but we reload in part to make our money and our components last longer than one shot and there is always that push-pull dilemma of getting “just one more shot” from a hull.
Petals on G/BP wads are designed to snap-away from the flying shot after it leaves your muzzle. According to Ballistic Products, this allows the pattern to expand evenly out to the fringes.
Fortunately, hulls occasionally give you easily discoverable clues about their readiness for retirement. Worn-out shells destroy shot-to-shot consistency. As hulls age, patterns and velocities can be affected by pressure fluctuations, so it is crucial that you quickly identify and dispose of flawed hulls. Inspect the base and walls of hulls for cracks and corrosion. Hulls with compromised structures will leak gas and cause the loss of pressure and velocity.
Hulls begin to fatigue with their first loading. Repeated reloading and firing eventually causes the seal between the base of the paper or plastic hull and its brass base, or the seal with the base wad, to deteriorate. In some hull types, the process of base degradation can be rapid and extreme, and therefore more noticeable than in others. Other symptoms of hull fatigue include plastic walls becoming brittle near the top or at the crimp and finally, developing hairline cracks that leak gas. You must toss these hulls immediately.
THE PRIMER
Beginning at the bottom of the hull, after re-sizing, your reloading press next extracts the spent primer and inserts a new one. Former editors of this book compared a loaded shotshell to an automobile engine; both required only a spark to begin the transformation from inertia to explosive power.
Struck by your gun’s firing pin, instantly super-heated, the tiny amount of chemical inside the primer in the base of a shell explodes. This supplies sudden, intense heat to the propellant by driving tiny white-hot particles upwards into it. The burning particles launch the propellant on the brief but glorious arc of its burn.
For maximum efficiency and effectiveness, a primer must offer the precise heat that a particular propellant load needs. Bulky, slow-burning powders for instance require a specific type of flame to ignite and burn properly. Too much heat and flame unnecessarily raise early chamber pressure, thereby “pushing the cycle.” Insufficient heat and flame do not ignite a large enough portion of the propellant for pressure to rise sufficiently before the chamber is decompressed by the load’s movement and the decreasing confinement.
The story of the primer began in about 1807 when Scottish hunter and inventor A. J. Forsyth discovered that a particular mixture of chemicals produced an explosion when it was struck. He realized that if the reaction was contained and channeled, it could be used to ignite powder charges and he eventually used his knowledge to create what was called a “pill lock” ignition system. His was the first step along the way to today’s modern primers and the path wound through England and America for more than a hundred years.
Unlike powder which burns very rapidly, the primer is designed to explode. The explosion of the tiny primer showers the powder with hot sparks and causes it to ignite.
MEC says their Steelmaster is the only shotshell reloader that comes specifically equipped to load steel shotshells and the bonus is that it works equally well for lead shot. The resize station handles brass or steel in either high or low base. The automatic primer feed is standard.
Early primer components were effective but terribly corrosive. Fulminate of mercury caused brass cases to become brittle. Potassium chlorate left thick deposits like common table salt inside a firearm, making bore cleaning necessary within hours.
Today, the #209 primer is the standard for shotshells, having thoroughly vanquished the slightly smaller Remington #157 about 40 years ago.
Modern ecological consciousness is making its presence felt even with shotshell primers. Lead styphnate, successfully used in primers for years, is non-corrosive, but the fear of non-degradable lead compounds in the environment may eventually eliminate its use, a clear example of change, not for shooting performance, but for its ecological consequence. Winchester now markets a non-toxic “Reduced Hazard Shotshell Primer” which lists, as its explosive ingredient, a 1- to 2-percent by volume chemical called Diazodnitro phenol. Winchester’s MSDS or Material Safety Data Sheet (rev. 01/01/04) quaintly notes, “Will explode with mechanical impact or shock.” On the other hand, Winchester’s MSDS (also 01/01/04) for basic lead styphnate (lead hydroxide styphnate, lead hydroxide 2,4,6 trinitroresorcinate), a more common explosive ingredient in primers today, notes also that it will explode with mechanical impact or shock. However, it also states that basic lead styphnate is a toxic explosive with known environmental dangers, and is known to cause cancer and birth defects.
Like powders, primers have a character that is all their own. Some burn longer and others burn with greater intensity. Some have a longer spark and produce heat over a much longer time – as long as several milliseconds lasts, that is – and this is referred to as the flame’s duration. In general, target loads do not need much spark, because the propellants are in the fast-burning, easily ignited category. Hunting loads, however, may require a great deal of primer boost and heat to get slow-burning propellants cooking. On a cold day, the need for tight crimps and warm primers can be critical to avoid sputtering ignition. For these loads, magnum primers were developed, an appellation that seems contrary to their typical application. Magnum primers are especially hot. Generally, however, magnum shotshells derive their power not from hotter primers but heavier shot payloads.
So do not fool yourself into believing that all primers are the same. They are not. Different primers produce varied results and cause distinct reactions as other shotshell components (type of powder, weight of load, shape of the hull) change. Although you would not want to have one explode in your closed fist, as the explosion would cause you permanent damage, by itself, a primer is not a significant pressure generator. While one type of primer produces minimal pressure in one load, another type might not. The same is true for maximum pressure. Except for this one thing – all arbitrary component-swapping creates new and unpredictable results – you cannot generalize about or substitute with primers. These small explosive elements and the energy they produce are a part of every load’s individual ballistic equation. Even if the pressure does not increase or decrease a great deal when you substitute the primer you have on hand rather than finding the primer you need, the balance created by a specific combination of components will suddenly be thrown off balance and the resulting load will be a below-average performer.
It is relatively easy to crank up the pressure in a load to well over the acceptable and safe prescribed pressure with just a primer swap. From a reloader’s point of view, this is the least desirable change. Tests indicate that some common target loads can change by as much as 3,500 psi with only a change of primer.
Here is a minor example from the 10-gauge tables of changing results from simply changing a primer. A quick search through the load data in this book will give you many more such examples. Let us hypothesize that you are using a single stage press to load 1-5/8-ounce lead shells and you have Blue Dot powder and Remington SP10 wads on hand.
Using a CCI 209M primer, the recipe calls for 45-grains of Blue Dot for an achievable velocity of 1,285 fps and a maximum chamber pressure of 8,000 psi.
Using a Winchester 209 primer, with the same 45-grain Blue Dot powder load gives you the same shot velocity – 1,285 fps – but raises the pressure in the chamber by 10 percent to 8,800 psi.
As of November, 2004 you could expect to pay between $95 and $100 for a case of 5,000 Remington, Winchester or Federal Primers or about $90 for Cheddite primers. On a per shot basis, this is about 2¢ or less.
THE WAD/SHOT CUP
Once you drop the powder in a hull, it is time to insert the “wad.” Now, a wad is a wad is a wad. Right? Of course, you know that could not be the case. If everything were that easy, we would not need books like this to guide reloading. A wad is a necessary and curious item in a shotshell. On the one hand, it is very simple and on the other hand, it is crucial to good, consistent performance.
I have said “it” as if there is a single wad that every handloader now uses, but that is not the case. In fact, during the past 150 years the wad has evolved as much as any other component of a shotshell. One way it has evolved is from paper or thick circlets of felt and cardboard to plastic, and now it is progressing toward special biodegradable materials such as those from Kent/Gamebore mentioned earlier in the chapter. Another way that it has evolved is from a flat disk or several stacked disks to … well, a pair of opposite facing cups with a springy cushion connecting them. Let’s talk about wads.
All primers are not the same. Not even all primers designated for shotshells are the same and they can not be interchanged without double checking load formulas. Many primers look alike and if you load multiple gauges, or multiple types of guns, keep your primers strictly separate.
The wad has two primary functions. It seals the powder from the shot and prevents the burning gas from leaking through the balls of shot or around the sides and thereby diminishing the unitary force of the shove down the barrel. Obviously, it must fit smoothly and with great precision against the sides of the hull, not so tight that it causes undue pressures from the burning powder, but not so loose that it does not completely seal off the gas.
Because the cardboard and felt wad circlets of a hundred years ago have evolved into a much more impressive and functional shotcup, the wad itself has accrued additional functions. By cupping the shot, it prevents significant contact between the accelerating pellets and the smooth steel of the barrel. Although this might leave residue inside the barrel for you to clean out later, lead would not damage the barrel.
Steel shot however has been known to scratch older barrels made from soft, relatively thin steel and to damage barrels with fixed chokes. There is certainly a question about some of the new pellet formulations, such as Federal’s tungsten-iron, which are designed to improve upon lead. Some of these products are harder than lead and are actually harder than the steel in the average shotgun barrel.
By minimizing contact between your steel barrel and the pellets in a load, the shotcup helps keep the accelerating pellets away from the hard barrel. The friction from such contact causes soft pellets to deform; it gives the otherwise relatively round pellets flat spots and these deformed pellets are pattern-wreckers, the so-called “flyers.” Thus, one function of a modern century wad or shotcup is to protect the pellets, and that is something a flat cardboard disk from the early 1900s could not do.
The Deci-Max is designed for extending 10-gauge versatility with lightweight shot charges and small shot sizes. It is pre-slit and recipes are available for this wad with lead, bismuth and Hevi-Shot.
The Competition Special 12-gauge wad from BPI is recommended for high performance shooting value on sporting clays courses. It features a double-crush section of “G” ring to cushions pellets during the setback phase of a shot.
Hevi-Shot requires wad columns or shotcups specifically designed for loading and shooting Hevi-Shot. The TPS 10-gauge shotcup series represents a culmination of many convergent technologies.
Once the shotcup has exited the barrel, it falls away quickly. Most modern wads are designed with petals so that the shotcup opens like a flower, the sides folding quickly backwards. Air resistance causes the shotcup, its petals now open like a parachute, to fall behind the pellets almost instantly. The wad usually falls to the ground within 10 to 15 yards, having completed its mission. (Older or experimental shotcups without petals often fell to the ground with some pellets remaining inside!) Un-slit wads (i.e., those without precut petals) are available, but with the intent that the reloader will slit them to a particular load and pattern preference.
What the old style flat disks could do, however – and what special disks can still do (refer to some of the recipe notes) – was to provide bulk when needed as reload recipes for powder and payload changed. Only one shotcup is used in a load today, but felt or cardboard wads can still be stacked if necessary when shell components change.
In separating the burning powder from the lead shot, the wad or shotcup helps prevent the extreme heat of the burning gas from melting the lead. Lead melts at 621.5 degrees Fahrenheit and boils at 3,164 degrees. According to Mike Daly at Hodgdon, today’s smokeless powders generate heat in the range of 2,800 to 3,200 degrees Kelvin. That computes to a range of 4,575 to 5,300 degrees Fahrenheit. That is easily hot enough to melt your lead shot if the temperature is sustained for more than a few seconds, which of course it is not. It is hot enough to fuse some of the pellets if these hot gases slip around the wad and decide to mingle. Imagine the havoc this will wreak with your carefully constructed shot pattern. Disastrous!
Curiously, reports on Hevi-Shot from Environ-Metal and Remington, show quite a bit of pellet deformation before a load is shot and this has not seemed to disrupt the patterns profoundly. Hevi-Shot is a blend of tungsten, nickel and iron that is actually heavier than lead – and still eco-friendly. This commentary should not be construed as a commercial for Hevi-Shot, only a report about characteristics that appear to differ from the normative expectation, but hunters and load testers alike attest to the lethality of this brand and composition. On the other hand, Kent/Gamebore notes that their Impact brand eco-friendly tungsten-matrix shot is not formulated to improve on lead. Thus, it is not harder than the steel in the typical shotgun barrel and does not require thick, protective plastic shotcups. Kent says its tungsten loads are just fine for fixed-choke guns as well as for sub gauges and guns with screw-in chokes and that these loads have the same “clean killing ballistic properties of lead.”
Another function of the wad/shotcup is to provide a flat, regular surface against which the expanding gases can press outward. A load of shot, even target #9, is porous, and buffered shot, which is only a load of shot whose spaces between the pellets are filled with sifted polyethylene particles, will allow gas to blow through unevenly if the shot is not backed by a wad or shotcup. The wad provides a ceiling against which the hot, expanding gas can press evenly, thrusting the shot down the barrel uniformly.
The wad also seals the gases behind the shotcup in an area of limited oxygen, an element that of course is required for combustion. Thus is the burning propellant limited in its burn rate and only by forcing the shot and wad down and out the barrel does complete combustion take place.
There are numerous shotcup designs from several internationally recognized manufacturers, but your chosen formula will note specific brands and styles: Remington SP16 or WAA 12R or CB 1034-28.
When building a specific load, use the specific components called for in the formula. Why? We have discussed the fact that there are several shell types for any gauge and that even though it might not be immediately obvious, some shells are straight-walled while others have tapered walls. A wad designed for use in a straight-walled Federal hull might not work to seal the gases properly in Winchester’s compression-formed AA hulls that have tapered walls. Winchester and a few other companies make wads with a smaller, angular base to fit these special hulls. In case a wad for straight hulls is used in a tapered hull, it will usually be a little on the large size, so you will have to make sure that your press seats it snugly. (Actually, this is not so rare in load recipes, but it is quite rare that a wad designed for a tapered hull will ever be recommended for a larger, straight-sided hull.)
Using the wrong wad can result in sub-par performance if it results in “powder migration” past the seal, or if significant “blow-by” (gas escaping around a load rather than pushing with all its force behind it) reduces load pressure and velocity. So variances in gas-sealing ability and the different pressures these hulls thereby produce are one reason never to substitute wads.
Most modern wads are designed to “obturate.” This means that the bell-shaped gas seal flares out slightly under pressure to create a self-sustaining seal. Engineers who design shotcups understand that a tight, consistent seal gives your load maximum drive and consistent ballistic performance.
High velocity loads require a tight gas seal in the hull and in the shotgun’s bore to achieve quality results. The modern phenomenon of back-boring or over-boring barrels, enlarging the bore diameter slightly beyond SAAMI standards, has become popular without much consideration of the procedure’s effect on the shotcup’s ability to seal the gas behind the load of shot. Of course, we are only talking about a few thousandths of an inch, a virtually impossible difference for the unaided human eye to distinguish, but it is significant in a manufacturing and shooting environment where the difference between success and failure is often no more than that. If gas escapes around the wad seal in an overbored barrel, velocity and pattern will suffer.
The problem of inadequate gas seal grows exponentially when shotcups from smaller, tapered shells are forced to carry maximum loads through overbored barrels. This is a mismatch, but you can easily correct it at the reloading bench.
As shot loads become heavier than the typical 1-1/8-ounce 12-gauge target loads, propellant charges become bulkier because larger amounts of slower burning powders are generally required, especially for strong hunting loads. As such, the powder charge tops off above the tapered base, rendering a tapered-base wad irrelevant. In such a load, tapered-base wads increase the risk of a poor load without any potential advantage. Consider instead using a wad with a larger, tighter fitting seal.
Today’s wad is essentially a slick, three-part shell element, but the center section – which we have not yet discussed – is as important as the sections on either end. The center is a cushion, in effect, a collapsible spring. Its job is to work like a shock absorber, although admittedly an extremely light one, and to progressively collapse, evenly and uniformly, without tipping and thereby applying greater pressure to one side of the load.
Because the modern wad is a relatively soft plastic, you can see the imprint of the shot in an expended wad. If you pick up a couple after you shoot, you will note the permanent impressions of individual pellets and this testifies to the force of the explosive burn that the wad must accommodate. This is caused by the vertical unevenness of the movement through the barrel. The rear shot pellets move prior to those at the head of the shell and this force shows in the spent shotcup. (For someone who has never quite understood how the inside of a wheel spins at a faster speed but at the same rpm as the outside of the wheel, this is all very mystical!) Perhaps you would expect this since within a millisecond, the pressure builds to around 10,000 psi and the load achieves terminal velocity within a few inches of travel.
The writers of a former edition of this book, Kurt Fackler and M.L. McPherson, likened the effects of the powder burn to a shock wave, causing the bottom layers of pellets to “squash themselves against the upper layers.” This shock, they said, was the equivalent of wrapping a towel around a hammer. The instant of most extreme shock and acceleration, which moves the pellets from zero fps to maybe 1,200 fps, is cushioned.
The Ballistic Products Gas Seal or BPGS helps the powder achieve a complete, cyclic burn, with the net result of consistently higher velocities and fewer unburned grains of powder.
BPGS wads are stackable, versatile enough to use in almost any type of hull and will load a huge assortment of recipes.
Cork wads protect the base of a shotcup in a magnum load. Different shot sizes vary the height of the load, so cork wads are placed beneath the shot. This reduces setback damage and brings the load up to perfect crimping height. These wads are light, dense, flexible and can be stacked to make your crimp just right.
Remington’s 870 Express Deer pump-action is available in every gauge except the 10. Its barrel is rifled so it can shoot slugs and sabots accurately to 100 yards – or even farther, with a properly-mounted scope, plenty of practice, and the right combination of primer and other components.
Heavy loads tend to diminish the effectiveness of the cushion. Heavier loads of shot and heavier loads of powder, compress the wad much more significantly than lighter field and target loads. Thus, the energy wave from the powder’s explosion is transferred more directly and harshly to the pellets. Probably, these heavy loads need additional cushioning in the way of felt spacers and special cushion wads that must be placed immediately below the charge of shot.
When reloading, you want this center section to compress, but not collapse. A total collapse would ruin its value and could perhaps damage or torque the gas seal. So, under the steady pressure of the wad ram, the cushion section should predictably compress to accommodate various powder heights.
We have spent quite a few pages discussing wads without mentioning the spreader or brush wad. These wads are usually made with no shotcup at all. Although outside pellets will be deformed by barrel scrub, your pattern will function very close to the true choke (a completely open barrel with no constriction) of your shotgun. Often used in guns with highly polished or chromed bores, brush wads give you exceptional results. A variation is a wad with a vertical “X” section in the center; these push a pattern much wider than the bore’s marked constriction.
