Handloading or reloading is the process of loading firearm cartridges or shotgun shells by assembling the individual components (case/shotshell, primer, powder, and bullet/shot), rather than purchasing completely-assembled, factory-loaded cartridges. Generally only Boxer-primed cases (see internal ballistics) are reloaded.
Historically, handloading referred to the private manufacture of cartridges and shells using all newly-manufactured components, whereas reloading referred to the private manufacture of cartridges and shells using previously-fired cartridge brass and shells with new bullets, shot, primers, and powder. In modern usage, however, no distinction is made in these terms, and they are considered synonymous.
Collectors of obsolete firearms often have to handload because cartridges are no longer commercially produced. Handloaders can also create cartridges for which there are no commercial equivalents, such as wildcat cartridges. As with any hobby, the pure enjoyment of the reloading process may be the most important benefit.
There are three aspects to ballistics: internal ballistics, external ballistics, and terminal ballistics. Internal ballistics refers to things which happen inside the firearm during and after firing but before the bullet leaves the muzzle. The handloading process can realize increased accuracy and precision through improved consistency of manufacture, by selecting the optimal weight and profile of the bullet, and tailoring the velocity of the bullet. Each cartridge reloaded can have each component carefully matched to the rest of the cartridges in the batch. Brass cases can be matched by volume and weight, bullets by weight and bearing surface, powder charges by weight, type, and case filling (the amount of empty space between the top of the charge and the base of the bullet). In addition to these items that are considered critical, the equipment used to assemble the cartridge also have an effect on its uniformity/consistency and optimal shape/size; dies used to size the cartridges can be matched to a given weapon's chamber. Modern handloading equipment enables a firearm owner to tailor fresh ammunition to a specific firearm, and to precisely-measured tolerances far exceeding the comparatively wide tolerances within which commercial ammunition manufacturers operate. Where the most extreme accuracy is demanded, such as in rifle benchrest shooting, handloading is a fundamental prerequisite for success.
The basic piece of equipment for handloading is the press. A press is a device that uses compound leverage to push the cases into the dies that perform the loading operations. Presses vary from simple, inexpensive single stage models, to complex progressive models that will eject a loaded cartridge with each pull of a lever, at rates of 10 rounds a minute.
Single stage presses, generally of the "O" or "C" types, are the simplest. They perform one step on one case at a time. When using a single stage press, cases are loaded in batches, one step for each cartridge per batch at a time. Batches are kept small, about 20-50 cases at a time, so that a batch is never left in a partially-completed state, as high humidity and light can degrade the powder. Single stage presses are commonly most used for high-precision rifle cartridge handloading, but may be used for high-precision reloading of all cartridge types, and for working up loads (developing loading recipes) for ultimately manufacturing large numbers of cartridges on a progressive press.
Turret presses, most commonly of the "C" type, are similar to single stage presses, but permit mounting all of the dies for one cartridge (or sometimes two cartridges) simultaneously, with each die being installed and correctly locked in position with lock rings onto the press at the same time. Batch operations are performed similar as to on a single stage press, but to switch dies, the turret is simply rotated, placing another die in position. Although turret presses operate much like single stage presses, they eliminate much of the setup time required in positioning individual dies correctly.
Progressive presses handle several shells at once, with each pull of the lever performing a single step on all the cases at once. Progressive presses hold all the dies needed, plus a powder measure and a primer feed, and often also include an additional station where the powder levels are checked, to prevent over or under charges. Progressive presses also often feature case feeds that will hold hundreds of cases to be loaded, and all the user has to do is hold the bullet in place over the appropriate case mouth, and pull the lever.
Shotshell presses are a special case, and are generally a single unit of the "H" configuration that handles all functions. Shotshell reloading is similar to cartridge reloading, except that instead of a bullet, a wadding and a measure of shot are used, and after loading the shot, the shell is crimped shut. The shotshell loader contains stations to resize the shell, measure powder, load the wad, measure shot, and crimp the shell. Due to the low cost of modern plastic shotshells, and the additional complexity of reloading fired shells, shotshell handloading is not as popular as cartridge handloading.
Standard dies are made from hardened steel, and require that the case be lubricated, for the resizing operation, which requires a large amount of force. Rifle cartridges require lubrication of every case, due to the large amount of force required, while smaller, thinner handgun cartridges can get away with alternating lubricated and unlubricated cases. Carbide dies have a ring of tungsten carbide, which is far harder and slicker than tool steel, and so carbide dies do not require lubrication.
Modern reloading dies are generally standardized with 7/8-14 (or, for the case of .50 BMG dies, with 1-1/4x12) threads and are interchangeable with all common brands of presses, although older dies may use other threads and be press-specific.
Dies for bottle neck cases usually are supplied in sets of at least two dies, though sometimes a third is added for crimping. This is an extra operation and is not needed unless a gun's magazine or action design requires crimped ammunition for safe operation, such as autoloading firearms, where the cycling of the action may push the bullet back in the case, resulting in poor accuracy and increased pressures. Crimping is also sometimes recommended to achieve full velocity for bullets, through increasing pressures so as to make powders burn more efficiently, and for heavy recoiling loads, to prevent bullets from moving under recoil. For FMJ bullets mounted in bottle neck cases, roll crimping is generally not ever used unless a cannelure is present on the bullet, to prevent causing bullet deformation when crimping. Rimless, straight wall cases, on the other hand, require a taper crimp, because they headspace on the case mouth; roll crimping causes headspacing problems on these cartridges. Rimmed, belted, or bottleneck cartridges, however, generally can safely be roll crimped when needed. Three dies are normally supplied for straight walled cases, with an optional fourth die for crimping. Crimps for straight wall cases may be taper crimps, suitable for rimless cartridges used in autoloaders, or roll crimps, which are best for rimmed cartridges such as are used in revolvers.
There are also some specialty dies worth mentioning. Bump dies are designed to move the shoulder of a bottleneck case back just a bit to facilitate chambering. These are frequently used in conjunction with neck dies, as the bump die itself does not manipulate the neck of the case whatsoever. A bump die can be a very useful tool to anyone who owns a fine shooting rifle with a chamber that is cut to minimum headspace dimensions, as the die allows the case to be fitted to this unique chamber. Another die is the "hand die". A hand die has no threads and is operated - as the name suggests - by hand or by use of a hand operated arbor press. Hand dies are available for most popular cartridges, and although available as full-length resizing dies, they are most commonly seen as neck sizing dies. These use an interchangeable insert to size the neck, and these inserts come in .001 steps so that the user can custom fit the neck of the case to his own chamber or have greater control over neck tension on the bullet.
A precision scale is a near necessity for reloading. While it is possible to load using nothing but a powder measure and a weight to volume conversion chart, this greatly limits the precision with which a load can be adjusted, increasing the danger for accidentally overloading cartridges with powder for loads near or at the maximum safe load. With a powder scale, an adjustable powder measure can be calibrated more precisely for the powder in question, and spot checks can be made during loading to make sure that the measure is not drifting. With a powder trickler, a charge can be measured directly into the scale, giving the most accurate measure.
A scale also allows bullets and cases to be sorted by weight, which can increase consistency further. Sorting bullets by weight has obvious benefits, as each set of matched bullets will perform more consistently. Sorting cases by weight is done to group cases by case wall thickness, and match cases with similar interior volumes. Military cases, for example, tend to be thicker, while cases that have been reloaded numerous times will have thinner walls due to brass flowing forward under firing, and excess case length being later trimmed from the case mouth.
Single stage presses often do not provide an easy way to prime cases. Various add-on tools can be used for priming the case on the down-stroke, or a separate tool can be used. Since cases loaded with a single stage press are done in steps, with the die being changed between steps, a purpose made priming tool is often faster than trying to integrate a priming step to a press step. A purpose made tool is also often more consistent than a model that fits on a single stage press, resulting in a more consistent primer seating depth.
Beginning reloading kits often include a weight to volume conversion chart for a selection of common powders, and a set of powder volume measures graduated in small increments. By adding the various measures of powder a desired charge can be measured out with a safe degree of accuracy. However, since multiple measures of powder are often needed, and since powder lots may vary slightly in density, a scale accurate to 0.10 grain (6.5 mg) is desirable.
Like any complex process, mistakes in handloading are easy to make. A bullet puller allows the handloader to disassemble mistakes. Most pullers use inertia to pull the bullet; they are shaped like hammers, and the case is locked in place inside. A sharp blow on a hard surface will suddenly stop the case, and the inertia of the heavy bullet will pull it free of the case in a few blows, trapping the powder and bullet in the body of the puller. Collet type pullers are also available, which use a caliber-specific clamp to grip the bullet, while the loading press is used to pull the case downwards. It is essential that the collet be a good match for the bullet diameter, because a poor match can result in significant deformation of the bullet.
Bullet pullers are also used to disassemble loaded ammunition of questionable provenance or undesirable configuration, so that the components can be salvaged for re-use. Surplus military ammunition is often pulled for components, particularly the cartridge cases, which are often difficult to obtain for older foreign military rifles. Military ammunition is often tightly sealed, to make it resistant to water and rough handling, such as in machine gun feeding mechanisms. In this case, the seal between the bullet and cartridge can prevent the bullet puller from functioning. Pushing the bullet into the case slightly with a seating die will break the seal, and allow the bullet to be pulled.
Primers are a more problematic issue. If a primer is not seated deeply enough, the cartridge (if loaded) can be pulled, and the primer re-seated with the seating tool. Primers that must be removed are frequently deactivated first—either firing the primed case in the appropriate firearm, or soaking in penetrating oil, which penetrates the water resistant coatings in the primer.
Components pulled from loaded cartridges should be reused with care. Unknown or potentially contaminated powders, contaminated primers, and bullets that are damaged or incorrectly sized can all cause dangerous conditions upon firing.
Cases, especially bottleneck cases, will stretch upon firing. How much stretch is based on load pressure, cartridge design, chamber size, and other variables. Periodically cases need to be trimmed to bring them back into proper specifications. Most reloading manuals list both a trim size and a max length. Long cases can create a safety hazard through improper headspace and possible increased pressure.
Several kinds of case trimmers are available. Die-based trimmers have an open top, and allow the case to be trimmed with a file during the loading process. Manual trimmers usually have a base that has a shellholder at one end and a cutting bit at the opposite end, with a locking mechanism to hold the case tight and in alignment with the axis of the cutter, similar to a small lathe. Typically the devices is cranked by hand, but sometimes they have attachments to allow the use of a drill or powered screwdriver. Powered case trimmers are also available. They usually consist of a motor (electric drills are sometimes used) and special dies or fittings that hold the case to be trimmed at the appropriate length, letting the motor do the work of trimming.
Primer pocket uniformer tools are used to achieve a uniform primer pocket depth. These are small endmills with a fixed depth-spacing ring attached, and are mounted either in a handle for use as a handtool, or are sometimes mounted in a battery-operated screwdriver. Some commercial cartridges (notably Sellier & Bellot) use large rifle primers that are thinner than the SAAMI standards common in the United States, and will not permit seating a Boxer primer manufactured to U.S. standards; the use of a primer pocket uniformer tool on such brass avoids setting Boxer primers high when reloading, which would be a safety issue. Two sizes of primer pocket uniformer tools exist, the larger one is for large rifle (0.130" nominal depth) primer pockets and the smaller one is used for uniforming small rifle/pistol primer pockets.
Flash hole uniforming tools are used to remove any burrs, which are residual brass remaining from the manufacturing punching operation used in creating flash holes. These tools resemble primer pocket uniformer tools, except being thinner, and commonly include deburring, chamfering, and uniforming functions. The purpose of these tools is to achieve a more equal distribution of flame from the primer to ignite the powder charge, resulting in consistent ignition from case to case.
The following materials are needed for handloading ammunition:
Case lubricant may also be needed, depending on the dies used.
When previously-fired cases are used, they must be inspected before loading. Cases that are dirty or tarnished are often polished in a tumbler to remove oxidation and allow easier inspection of the case. Cleaning in a tumbler will also clean the interior of cases, which is often considered important for handloading high-precision target rounds. Cracked necks, non-reloadable cases (steel, aluminum, or Berdan primed cases), and signs of head separation are all reasons to reject a case. Cases are measured for length, and any that are over the recommended length are trimmed down to the minimum length. Competition shooters will also sort cases by brand and weight to ensure consistency.
Removal of the primer, called decapping, is usually done with a die containing a steel pin that punches out the primer. Berdan primed cases require a different technique, either a hydraulic ram or a hook that punctures the case and levers it out from the bottom. Military cases have crimped-in primers, and decapping leaves a slight ridge that inhibits seating a new primer. A reamer or a swage is used to remove this crimp.
When a cartridge is fired, the internal pressure expands the case to fit the chamber in a process called obturation. To allow ease of chambering the cartridge when it is reloaded, the case is swaged back to size. Competition shooters, using bolt action rifles which are capable of camming a tight case into place, often resize only the neck of the cartridge, called neck sizing, as opposed to the normal full length resizing process. Neck sizing is only useful for cartridges to be re-fired in the same firearm, as the brass may be slightly oversized in some dimensions for other chambers, but the precise fit of case to chamber will allow greater consistency and therefore greater potential accuracy. Some believe that neck sizing will permit a larger number of reloads with a given case in contrast to full size resizing, although this is controversial. Semi-automatic rifles and rifles with SAAMI minimum chamber dimensions often require a special small base resizing die, that sizes further down the case than normal dies, and allows for more reliable feeding.
Once the case is sized down, the inside of the neck of the case will actually be slightly smaller than the bullet diameter. To allow the bullet to be seated, the end of the neck is slightly expanded to allow the bullet to start into the case. Boattailed bullets need very little expansion, while unjacketed lead bullets require more expansion to prevent shaving of lead when the bullet is seated.
Priming the case is the most dangerous step of the loading process, since the primers are pressure sensitive. The use of safety glasses or goggles during priming operations can provide valuable protection in the rare event that an accidental detonation takes place. Seating a Boxer primer not only places the primer in the case, but it seats the anvil of the primer down onto the priming compound, in effect arming the primer. A correctly seated primer will sit slightly below the surface of the case. A primer that protrudes from the case may cause a number of problems, including what is known as a slam fire which is the firing of a case before the action is properly locked when chambering a round. This may either damage the gun, and/or injure the shooter. A protruding primer will also tend to hang when feeding, and the anvil will not be seated correctly so the primer may not fire when hit by the firing pin. Primer pockets may need to be cleaned with a primer pocket brush to remove deposits that prevent the primer from being properly seated. Berdan primers must also be seated carefully, and since the anvil is part of the case, the anvil must be inspected before the primer is seated. For reloading cartridges intended for use in military-surplus firearms, rifles especially, "hard" primers are most commonly used instead of commercial "soft" primers. The use of "hard" primers avoids slamfires when loading finished cartridges in the military-surplus firearm. Such primers are available to handloaders commercially.
The quantity of gunpowder is specified by weight, but almost always measured by volume, especially in larger scale operations. A powder scale is needed to determine the correct mass thrown by the powder measure, as loads are specified with a precision of 0.10 grain (6.5 mg). One grain is 1/7000 of a pound. Competition shooters will generally throw a slightly underweight charge, and use a powder trickler to add few granules of powder at a time to the charge to bring it to the exact weight desired for maximum consistency. Special care is needed when charging large capacity cases with fast burning, low volume powders. In this instance, it is possible to put two charges of powder in a case without overflowing the case, which can lead to dangerously high pressures and a significant chance of bursting the chamber of the firearm. Non-magnum revolver cartridges are the easiest to do this with, as they generally have relatively large cases, and tend to perform well with small charges of fast powders. Some powders meter (measure by volume) better than others due to the shape of each granule. When using volume to meter each charge, it is important to regularly check the charge weight on a scale throughout the process.
Competition shooters also often sort bullets by weight, often down to 0.10 grain (6.5 mg) increments. The bullet is placed in the case mouth by hand, and then seated with the press. At this point, the expanded case mouth is also sized back down. A crimp can optionally be added, either by the seating die or with a separate die. Taper crimps are used for cases that are held in the chamber by the case mouth, while roll crimps may be used for cases that headspace on a rim or on the cartridge neck. Roll crimps hold the bullet far more securely, and are preferred in situations, such as magnum revolvers, where recoil velocities are significant. A tight crimp also helps to delay the start of the bullet's motion, which can increase chamber pressures, and help develop full power from slower burning powders (see internal ballistics).
Handloaded ammunition is not recommended for defensive use. Experts point to potential legal liabilities that the shooter incurs if using handloaded ammunition for defense, such as an implied malice on the part of the shooter, as the use of handloaded ammunition may give the impression that "regular bullets weren't deadly enough". Additionally, forensic reconstruction of a shooting relies on using identical ammunition from the manufacturer, where handloaded ammunition cannot be guaranteed identical to the ammunition used in the shooting, since "the defendant literally manufactured the evidence".
Many firearms manufacturers abdicate responsibility for the operation and safety of their arm when untested ammunition is fired. Generally, this means that the maker's warranty is void and the manufacturer not liable for any damage to the gun or personal injury if handloaded ammunition is used which exceeded established limits for a particular arm. This arises because firearm manufacturers point out that while they have some influence and scope for redress with ammunition manufacturers, they have no such influence over the actions of incompetent or over-ambitious individuals who assemble ammunition.
It is typically agreed that rimfire cartridges (e.g. .22 Long Rifle) are not hand-loaded, although there are some shooters that unload commercial rimfire cartridges, and use the primed case to make their own loads, or to generate special rimfire wildcat cartridges. These cartridges are highly labor intensive to produce.
Some shooters desiring to reload for obsolete rimfire cartridges alter the firearm in question to function as a centerfire, which allows them to reload. Even if custom brass must be manufactured, this is often far less expensive than purchasing rare, out of production ammunition. Cartridges like the .56-50 Spencer, for example, are not readily obtainable in rimfire form, but can be made from shortened .50-70 cartridges or even purchased in loaded form from specialty dealers.
An unusual solution to the problem of obtaining ammunition for the very old pinfire cartridges is even available. This solution uses specialized cartridges that use a removable pin and anvil which hold a percussion cap of the type use in caplock firearms. To reload a fired case, the pin is removed, allowing the anvil to slide out; a percussion cap is placed in the anvil, it is re-inserted, and the pin serves to lock the anvil in place, as well as to ignite the percussion cap.
Shotshell reloading is sometimes done for scatter shot loads, consisting of multiple wads separating groups of shot, which are intended for use at short distance hunting of birds. Similarly, shotshell reloading for buck shot loads and non-lethal "bean bag" loads are sometimes handloaded. These types of shotshells are rarely handloaded.
Precision and consistency are key to developing accurate ammunition. Various methods are used to ensure that ammunition components are as consistent as possible. Since the firearm is also a variable in the accuracy equation, careful tuning of the load to a particular firearm can yield significant accuracy improvements.
The neck of the case is another variable, since this determines how tightly the bullet is held in place during ignition. Inconsistent neck thickness and neck tension will result in variations in pressure during ignition. These variables can be addressed by annealing and thinning the neck, as well as by careful control of the crimping operation.
The transition from case to barrel is also very important. If the bullets have to travel a varying distance from the case to the point where they engage the rifling, then this can result in variations in pressure and velocity. The bearing surface of the bullet should ideally be seated as close as possible to the rifling. Since it is bearing surface that matters here, it is important that the bullets have a consistent bearing surface.
While the case is usually the most expensive component of a cartridge, the bullet is usually the most expensive part of the reloaded round, especially with handgun ammunition. It is also the best place to save money with handgun ammunition. This is because the bullets are used one time, and the case lasts for many reloadings.
For the truly frugal, the cheapest method of obtaining bullets intended for use at low to moderate velocities is to cast them. This requires a set of bullet molds, which are available from a number of sources, and a source of known quality lead. Linotype and automotive wheelweights are often used as sources of lead that are blended together in a molten state to achieve the desired Brinell hardness. Other sources of scrap lead, such as recovered bullets, lead cable sheathing, lead pipe, or even lead-acid battery plates, can yield usable lead with some degree of effort, including purification and measuring of hardness.
Other advantages of casting bullets, or swaging them from lead wire (which is pricer but avoids many quality control issues of casting) is the ability to precisely control many attributes of the resulting bullet. Custom bullet molds are available from a number of sources, allowing the handloader to pick the exact weight, shape, and diameter of the bullet to fit the cartridge, firearm, and intended use. A good example of where this is useful is for shooters of older military surplus firearms, which often exhibit widely-varying bore and groove diameters; by making bullets specifically intended for the firearm in question, accuracy of the resulting cartridges can be significantly increased.
Cast bullets are also the cheapest bullets to buy, though generally only handgun bullets are available in this form. Some firearms manufacturers, such as those using polygonal rifling like Glock and H&K, advise against the use of cast bullets. For shooters who would like to shoot cast bullets, aftermarket barrels are generally available for these models with conventional rifling, and the cost of the barrel can generally be recouped in ammunition savings after a few thousand rounds.
Soft lead bullets are generally used in handguns with velocities of 1000 ft/s (300 m/s) or lower, while harder cast bullets may be used, with careful powder selection, in rifles with velocities of 2000 ft/s (600 m/s) or slightly more. The limit is the point at which the powder gas temperature and pressure starts to melt the base of the bullet, and leave a thin coating of molten and re-solidified lead in the bore of the gun—a process called leading the bore. Cast lead bullets may also be fired in full power magnum handgun rounds like the .44 Magnum with the addition of a gas check, which is a thin zinc or copper washer or cup that is crimped over a tiny heel on the base of appropriate cast bullets. This provides protection for the base of the bullet, and allows velocities of over 1500 ft/s (450 m/s) in handguns, with little or no leading of the bore.
Most shooters prefer jacketed bullets, especially in rifles and pistols. The hard jacket material, generally copper or brass, resists deformation and handles far higher pressures and temperatures than lead. Several companies offer swaging presses (both manual and hydraulic) that will manufacture on a small scale jacketed bullets that can rival or surpass the quality of commercial jacketed bullets. Two swaging equipment manufacturers offer equipment and dies designed to turn .22 Long Rifle cases into brass jackets for .22 caliber (5.56 mm) bullets. Handloaders have the choice to swage but most choose to purchase pre-made jacketed bullets, due to the obscure nature of swaging and the specialized equipment. The process of manufacturing a jacketed bullet is far more complex than for a cast bullet; first, the jacket must be punched from a metal sheet of precise thickness, filled with a premeasured lead core, and then swaged into shape with a high pressure press in multiple steps. This involved process makes jacketed bullets far more expensive on average than cast bullets. Further complicating this are the requirements for controlled expansion bullets (see terminal ballistics), which require a tight bond between the jacket and the core. Premium expanding bullets are, with match grade bullets, at the top tier in expense.
A more economical alternative was made available to the handloader in the 1980s, the copper plated bullet. Copper plated bullets are lead bullets that are electroplated with a copper jacket. While thinner than a swaged bullet jacket, the plated jacket is far thicker than normal electroplate, and provides significant structural integrity to the bullet. Since the jacket provides the strength, soft lead can be used, which allows bullets to be swaged or cast into shape before plating. While not strong enough for most rifle cartridges, plated bullets work well in many handgun rounds, with a recommended maximum velocity of 1250 ft/s (375 m/s). Plated bullets fall between cast and traditional jacketed bullets in price.
While originally sold only to handloaders as an inexpensive substitute for jacketed bullets, the plated bullet has come far. The ammunition manufacturer Speer now offers the Gold Dot line, commercially loaded premium handgun ammunition using copper plated hollow point bullets. The strong bond between jacket and core created by the electroplating process makes expanding bullets hold together very well, and the Gold Dot line is now in use by many police departments.
Since the case is the single most expensive part of a loaded round, the more times a case can be re-used, the better. Cases that are loaded to a moderate pressure will generally last longer, as they will not be work hardened or flow under pressure as much as cases loaded to higher pressures. Use of moderate pressure loads extends the life of the case significantly, not to mention saving quite a bit of wear and tear on the barrel. Work hardening can cause cracks to occur in the neck as the hardened brass loses its malleability, and is unable to survive swaging back into shape during the resizing operation. Rifle brass tends to flow towards the neck (this is why rifle brass must be trimmed periodically) and this takes brass away from the rear of the case. Eventually, this will show as a bright ring near the base of the cartridge, just in front of the thick web of brass at the base. If brass is used after this ring appears, it risks a crack, or worse, a complete head separation, which will leave the forward portion of the brass lodged in the chamber of the gun. This generally requires a special stuck case removal tool to extract, so it is very undesirable to have a head separation.
With bottlenecked cartridge cases, choosing the right sizing die can also have an impact. Full length sizing of cartridges is often thought to greatly shorten case life by work hardening the full length of the case, which can cause the case neck to split, although some studies show that the number of reloads possible with a case is essentially the same for either full length sizing as for neck sizing only if the issue is one of neck hardening. If the reloaded cartridges are going to be used in the same firearm in which they were previously fired, though, and if that firearm has a bolt action or other action with a strong camming action on closing, then full length resizing may not be needed. A collet neck sizing die can be used to size just the case neck enough to hold the bullet, and leave the rest of the case unsized. The resulting cartridge should be able to fit back into the specific rifle that previously fired it, though the fit will be tight and require more force to chamber than a full length resized case, especially on rifles with factory chambers which tend to be out of round. The use of a neck sizing die in conjunction with moderate pressure loads may extend the life of the case significantly by minimizing the amount of case that is work hardened or stretched. This is especially true for reloads intended for military rifles with intentionally large chambers such as the Lee-Enfield in .303 British. The use of partial length or neck sizing for cartridges used in such large chambers permits effectively switching the headspacing from relying on the rim of a rimmed cartridge to the shoulder of the bottle neck transition instead, increasing the number of times a rimmed military cartridge can be reloaded from once to perhaps 5 or more times, all while avoiding dangerous incipient head separations. One final form of limiting case wear is, unfortunately, limited strictly to benchrest shooters with custom-cut chambers. The chamber of these rifles is cut so that there is just enough room, typically just a few thousandths of an inch, in the neck area. The result of using this type of chamber is that fired rounds don't require any resizing whatsoever once the case is fired. The brass will 'spring back' a bit after firing, and will properly hold a new bullet without further manipulation. Some refer to this as a 'fitted' neck, however it is a function of both the carefully cut precision neck and the case adjusted to fit with very little clearance.
Work hardening happens to all cases, even low pressure handgun cases. The sudden increase in pressure upon firing hits the brass like a hammer, changing its crystalline structure and making it more brittle. The neck of the case, if it becomes too brittle, will be incapable of standing the strain of resizing, expanding, crimping, and firing, and will split during loading or firing. While a neck split during firing is not a significant danger, a split neck will render the case incapable of holding the bullet in place, so the case must be discarded or recycled as a wildcat cartridge of shorter overall length, allowing the split section to be removed. The simplest way to decrease the effects of work hardening is to decrease the pressure in the case. Loading to the minimum power level listed in the reloading manual, instead of the maximum, can significantly increase case life. Slower powders generally also have lower pressure peaks, and may be a good choice.
Annealing brass to make it softer and less brittle is fairly easy, but annealing cartridge cases is a more complex matter. Since the base of the case must be hard, it cannot be annealed. What is needed is a form of heat treatment called differential hardening, where heat is carefully applied to part of the case until the desired softness is reached, and then the heat treatment process is halted by rapidly cooling the case. Since annealing brass requires heating it to about 660 F (350 C), the heating must be done in such a way as to heat the neck to that temperature, while preventing the base of the case from being heated and losing its hardness. The traditional way is to stand the cases in a shallow pan full of water, then heat the necks of the cases with a torch, but this method makes it difficult to get an even heating of the entire case neck. A temperature sensitive crayon can be used at the point to which it is to be annealed, which is just behind the shoulder for bottlenecked cartridges, or at the bottom of the bullet seating depth for straight wall cartridges. The neck of the case is placed in a propane torch flame and heated it until the crayon mark changes color, indicating the correct temperature. Once the correct temperature is reached the case is completely quenched in water to stop the annealing process at the desired hardness. Failing to keep the base of the case cool can anneal the case near the head, where it must remain hard to function properly. Another approach is to immerse the case mouth in a molten alloy of lead that is at the desired annealing temperature for a few seconds, then quickly shake off the lead and quench the case.
Cases that have small cracks at the neck may not be a complete loss. Many cartridges, both commercial and wildcats, can be made by shortening a longer cartridge. For example, a .223 Remington can be shortened to become a .222 Remington, which can further be shortened to become a .221 Fireball. Similarly, .30-06 Springfield can become .308 Winchester, which can become .308 x 1.5 or any number of specialized benchrest shooting cartridges. Since the cracking is likely due to a brittle neck, the cases should be annealed before attempting to reform them, or the crack may propagate and ruin the newly-formed shorter case as well.
The tradeoff comes in terms of power and accuracy; AA #2 is designed for small cases, and will burn inconsistently in the large .44 Magnum case. AA #9, however, will fill the case much better, and the slow burn rate of AA #9 is ideal for magnum handgun rounds, producing 20% higher velocities (at maximum levels) while still producing less pressure than the fast burning AA #2. A medium burning powder might actually be a better choice, as it could split the difference in powder weights while delivering more power and accuracy than the fastest powder.
One solution that is applicable to revolvers in particular is the possibility of using a reduced-volume case. Cartridges such as .357 Magnum and .44 Magnum are just longer versions of their parent rounds of .38 Special and .44 Special, and the shorter rounds will fire in the longer chambers with no problems. The reduced case capacity allows greater accuracy with even lighter loads. A .44 Special loaded with a minimum load of AA #2 uses only 4.2 grains (0.27 g) of powder, and produces a modest 771 ft/s (235 m/s).
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