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If you don't find the answer here, you can ask an engineer. Click here to use e-mail. But first, read this and see if we might have anticipated your question. It will save you time, and you'll pick up other ideas that you might not have thought to ask about. Or, you can view, download, or print a text-only (fast) question/answer sheet by clicking |
A. You can get everything you need from Corbin, and there are hundreds of suppliers for raw material such as lead and copper. Lead for the cores can be cast from scrap material, extruded into wire using our extruder dies in the hydraulic presses, or purchased in spools and simply cut to length with a core cutter. Corbin makes both core moulds and core cutters. The moulds use scrap or ingots, the cutters use extruded lead wire. You can make the wire, or buy it. Corbin has all the equipment to handle the production at whatever level you wish. Corbin jackets can be purchased in bags of 250 or 500, ready made, in some cases. Some more exotic or unusual calibers you need to make yourself. We furnish kits to make jackets from fired 22 cases, shotgun primers, copper tubing, copper strip, and even solid copper rod. You can also use our Base Guard disks to eliminate the need for both hard lead and lubricant or jackets in many instances (up to 1400 fps). Corbin publishes the World Directory of Custom Bullet Makers, which also lists 200 sources of lead and 200 sources of copper jacket material, including tubing and strip. The book, Cat.No. WD-1, directly from Corbin. It is not included in the 7-book library, includes all the other books in print about bullet swaging. A. If you make only the same quality as mass produced bullets, you are doing something wrong! The swaging equipment Corbin provides is identical to that used by Olympic champions, International Shooting champions, defense and security forces world wide, the military R&D labs... in other words, this is the most precise way known to make good bullets. It is capable of vastly superior bullets to mass produced slugs, because every single one is hand made by you, and you can inspect and adjust every component that goes into the bullet, matching the length, weight and diameter precisely to get the best results from your particular gun. You don't have to compromise because of market pressure or the lowest common denominator among buyers or even price of parts: if another penny put toward better material gives you what you want, there is no marketing department to tell you NO! You don't have to compete with any other company for market share: you just have to please yourself. If you want to try a different shape or weight or nose style or construction, no one can stop you. And who knows? -maybe it works better than the common design sold to the average shooter on the mass market. Over 400 custom bullet businesses using Corbin equipment have found this to be true -- and are selling the results! That is what has kept Corbin at the forefront of high performance bullet design for the past 30 years. A. The answer to this really depends on the shape, style, and construction of the bullet. But in general, you put material into a die (the die is a cylinder that holds the pressure) and apply pressure through an external and, in most dies, an internal, punch. The punch is a rod shaped and fitted to the die cavity. (Please don't say "die", "rod", "stem", or "ram" when you mean "punch"...it is confusing, and you may not get what you actually wanted! There are not that many terms to learn...the die, internal punch, and external punch are the three necessary components in a single "die" package or set. Sets can be one die complete with punches, or a number of dies that work together to make a certain bullet.) The pressure is always applied to the "core" or filler material, which expands to fill up the inside of the cup or jacket (the skin of the bullet). The jacket is supported by the die walls and, in some operations, the internal punch end. Otherwise it would be ruptured by the high pressure. Instead, it is forced to expand outward until it takes on the exact shape and size of the die cavity and punch end. Usually, a jacketed bullet is made in a 3-step operation. There are three dies, the core swage (which makes the rough cast or cut piece of lead wire into a precise diameter, length, and weight), the core seater (which applies pressure to the core and expands the jacket to correct diameter), and the point former (which puts the ogive or nose curve on the bullet). These three basic operations are expanded by using two special shapes of core seater die for making rebated boattails, instead of the usual flat base die, or by adding a lead tip shaping die to produce small lead tips on a rifle bullet after the ogive is formed. The various "die sets" which consist of from 1 to 6 dies are just combinations, and variations of the basic 3-die set. A lead bullet with a shoulder between the nose and shank (semi-wadcutter shoulder) can be made in a single die that combines the bleed holes of the core swage with the diameter of the core seater, and also finishes the nose and base against the ends of the internal and external punches. The reason this simple process with one die always produces a bullet with a shoulder is that the punch edge has to be at least .015 inches thick to survive the high pressure, and this punch edge is what forms a shoulder. The punch that forms the nose has a cavity machined into its tip, a mirror image of the nose you want to make. It can be round, Keith, flat, or any other shape so long as lead can go in, and come out again! In other words, you would have no luck with a shape that was larger inside the cavity than at the mouth...the lead would go in, but it wouldn't be able to come out again. This is OK, because very few designs could be used that had a bulb-shaped nose on the bullet in any case! If you want to make a smooth curve on the bullet, then it takes a minimum of two dies: the core seater, or for lead bullets a Lead Semi-Wadcutter die, and the point former. The point forming die forms the nose against the curved die wall itself, and only uses the internal punch to push the bullet out by its very tip (from .061 to .120 inch diameter ejection pin size on the internal PF punch). The reason for the lead tip forming die which is sometimes used for making smaller lead tips on jacketed rifle bullets is that the ejection pin punch leaves a small flat where it pushes the bullet out. If this is objectionable in a given design (usually only in the more pointed spitzer ogives), then the lead tip forming die can "clean up" the end of the bullet and give you a sharp tip or a small radius instead of the small flat. For step-by-step instructions, download the appropriate instruction sheet from our "Downloads" page for the die set you plan to use. The most basic die is the LSWC-1 (-M, -S, or -H is attached to the end of the catalog number to indicate the diameter, threads, and punch size. Dies with -R suffix can be used in a reloading press). The die set most people need for either rifle or pistol calibers is the FJFB-3-, which consists of a core swage, core seater, and point form die (please don't confuse the lead tip die with the point form die...the LT-1 lead tip die can only be used to reshape the tips of already-formed bullets, whereas the PF-1 point form die actually puts the ogive curve on the bullet). Your best understanding of bullet swaging will come from reading the Corbin Handbook of Bullet Swaging, and/or the book "ReDiscover Swaging". You can download the text portion of the Corbin Handbook from our "download" page. A. We make dies for reloading presses, provided the press is of the RCBS style with 7/8-14 tpi head and the famous RCBS slotted ram (our -R punches slip into the slot just like a shell holder). As to other kinds of swaging presses, certainly, if you send us the press, or sample dies, or even good drawings, we can probably build custom swaging dies to fit it. However, it is often wiser to spend the extra money on one of the Corbin presses, so that all your future dies can be standard rather than custom built. The parts will most likely be "in stock" or at least easily reproduced from our standard drawings, if you lose or break something. It makes sense to invest in tooling that has a future, rather than something which will always require more custom work, or a press from one of the one-person hobby sources who only makes a few now and then, and changes the design frequently. That works fine for self entertainment, but making products for the public presumes you'll be making parts and supporting the design as long as you are in business. A one-person shop usually is out of business as soon as the health or interests of the one person change. It would seem wiser to rely on a source with a long history of support, and a business structure that allows it to continue without regard to any one person's whims. Custom work can be expensive, because it means removing a skilled die-maker from regular production, and dedicating their time to a one-of-a-kind project that has little or no chance of producing other off-setting income. The overhead of keeping a well-supplied support system, with machinery, parts, buildings and people available to take care of your future swaging needs means that custom work will cost considerably more than production work. It doesn't take long to spend as much trying to use an obsolete or odd-ball press as it would to just buy a standard Corbin press and the regular dies that fit it. But we're willing to help, if you want to use something else. The price isn't made high just to discourage you, but because it really does cost that much in lost production. Regular production work also has the benefit of constantly refining and developing our processes to become ever more efficient. Custom work is like starting from scratch every time we make something, compared to building another die set to our own standards and dimensions. We can make several of our own dies in the time it takes to develop the prints, set aside the materials, and plan the production of a single custom set. A. From zero cents to perhaps as much as thirty cents, in rough terms: depends entirely on the material needed to make it. You can make free .224 and .243 bullets using fired .22 cases and scrap le ad that you pick up from the range. You can make free 25 acp bullets from fired shotgun primer cups. A typical benchrest quality bullet made with the best commercial jacket available would cost about seven cents. A bonded core, partitioned, rebated-boattail heavy-wall ultra-low drag .475 bullet might cost you as much as twenty cents in materials, if you bought them all in small quantity (copper tubing and lead wire, for instance). But to buy that same bullet, you'd pay over $1.50 from one of the custom bullet firms -- and chances are, you'd be making something they didn't even offer, at any price! If you make a lead bullet, it costs no more than a cast lead bullet. But it is usually 100 times more round and precise, 10 times more consistent in weight than the best cast bullets. A. The main reason Corbin dies cost from 1/10 to 1/5 that of other high quality benchrest grade dies is the fact that Corbin builds more dies in a month than the combined output of every die-maker in the world for a year! We have developed the "semi-custom" production method, where we group dies into four basic categories depending on the press, build a limited number of presses that work best with each bullet classification, and then make thousands of blank parts (punch blanks, die blanks, retainer bushings, and so forth) that can be built in the efficient mass production way, but then stored and finished by hand as the orders are completed. Our die-makers have so much experience compared to the one-man, hobby-business that is typical of the benchrest trade, that any of them can tell you how to build a .12 caliber or a 25mm bullet, and anything in between. They have learned tricks and developed trade secrets that apply from one special bullet to the others, things that a person who only made one or two calibers would never come across and never learn to use. Most benchrest-only shops only make a couple of calibers, so they don't get the exposure to new ideas that a die-shop building thousands of calibers and styles would. Some of these new ideas make the standard calibers better, and some just make it possible to build them faster and easier without any loss of quality. The net result is, Corbin's die-works has put in more than 30 years getting it right, making the process more and more efficient, and keeping the costs far below what a solitary die-maker would spend working alone to make the same thing, in far less quantity. A. Corbin swage dies are made from a proprietary high-carbide content die steel, which provides about 1/3 the wear life of GE Carboloy (a common solid ferrous carbide material) for about 1/10 the cost. A swage die made of the typical forms of solid carbide would, under conditions of high temperature caused by rapid automatic stroking, perhaps make 3 million bullets before it wore beyond normal acceptable tolerances, whereas our dies would make perhaps 1 million bullets before reaching the same point of wear. However, since our dies cost about 1/10 as much as the typical solid carbide die, you could buy ten of ours for the same price as one of those. And, to have the same wear life, you would only need three. Therefore, you would come out FAR ahead to make your three million bullets in three sets of our dies, instead of one solid carbide die! Also, you would have three points in that production period when the tolerances were at zero or starting point, instead of spending years making bullets that were half-way to "worn out" tolerances. But let's get real: most people will never make one million bullets, much less three million, in their lifetime. So why pay for it? Why not get tooling that is just as precise, makes just as accurate a bullet, but is far better priced and suited to your actual needs? And if you DO make more than a million bullets and wear a die slightly larger, you are STILL money ahead to get a second set for the next million, and a third set for the third million. Think it is likely?
Building diamond lapped high-carbide content steel dies rather than solid carbide dies is a conscious decision we made, based on the value and application. Nearly all our dies are used in hand or hydraulic presses, which stroke less than four or five times per minute. All the heat built up by friction is radiated away into the press frame, and into the air, by the time the next stroke is made. The main purpose of solid carbide dies is to resist softening of the die from high temperature, which would happen in a punch press application at 40 strokes per minute. For a high speed punch press, we would build the dies from solid carbide to resist heat softening, which then would accelerate the wear. For hand and hydraulic power presses, it seems a great waste of your money to try to convince you to spend $1500 to $2000 on a solid carbide die, when we can make just as precise, just as good a die using a steel matrix around free carbide particles, for less than $250, often substantially less. And you need a set of at least three dies to make jacketed bullets. The term "carbide" is often misunderstood, and so it is possible for it to be used much as the term "chlorophyl" was used in the 1950-60 marketing period: a vaguely understood reference to something that magically made everything from toothpaste to underwear "better" than if it didn't contain this mysterious green substance from plants. Of course, a marketer's dream is a term that everyone assumes means "better" without knowing why or how. That is the status of the term carbide among many handloaders today. In any tool steel, it is primarily the free carbide that gives the steel its hardness. Iron and carbon combine at high temperature to make a ferrous carbide, but separate again if the metal is cooled too slowly. Hardening steel is done by quickly lowering its temperature to "freeze" the crystals of carbide in the matrix of iron, so you have both the hardness and wear resistance of the carbide AND the flexibility and breakage resistance of the iron. A solid carbide die is more brittle than one which still has some iron matrix around the carbides. The hardness is a matter of how much iron is converted to ferrous carbide, as well as the action of certain alloying agents in the steel. Therefore, all steels have some carbide in them, because that is primarily what provides their hardness. Removing more and more of the iron by combining it with carbon eventually would turn the material into solid carbide, which is quite hard, but quite brittle. If a person wishes to have their dies last a long time, there are two factors to consider. One is the wear resistance, and the other is the ability to handle excess stress. A properly heat treated die steel will be able to expand and return to original size without cracking, over a much further range of stresses than a solid carbide die. In a single-purpose industrial application, where the machinery is calibrated to provide just the right force, and long experience has taught the die-makers the proper clearances for a particular job, it is not only acceptable but highly desirable to use very hard dies which may not take much abuse, but will wear a long time under the right conditions. In a home swaging operation, where you can apply any amount of force at any time, at your whim, and nothing will stop you from it except the eventual breakage of the die, it seems very risky to build a die so hard that it would wear several lifetimes of the average handloader's use, but might break instantly with a slight misapplication of pressure. Our judgement call is to make dies that would last far longer than the average home or small business user would ever need (most custom or home bullet makers seldom exceed 500,000 bullets in a lifetime), while still giving them the widest possible margin for error in applying pressure. This approach lets us build dies quickly by machining, hardening, and then diamond lapping the final tolerances, rather than the long and expensive process of electro-chemical machining which is required when one begins with a very hard material rather than one which can be made very hard later. Our typical swage die's Rc hardness is in the 60-62 range, which is well within the range of many grades of carbide (there is not just one thing called "carbide" but a whole range of alloys and grades, most of which are as different from each other as the various alloys of die and tool steel). As a result, you get just as good, if not better, dies which will, for all practical purposes, last as long as you will ever need, for a tiny fraction of the cost of solid carbide. There is no difference in the quality of bullet you can build. The only advantage of carbide would be for use in high speed punch presses, where the material would retain its hardness at higher temperature. As with most technical issues, it takes far longer to explain the facts, than it does to whip out a marketing phrase that sounds feasible. Carbide is better...why? Just because "everyone" says so? Why do they think so...because advertising told them to? This is why thinking people tend to get the better deals, because they take the time to understand the facts behind the rhetoric, and then decide for themselves. Those who just react without thinking may find that they have paid far beyond what was really necessary, and gotten no more benefit for it. A wonderful example is the 1999-2001 series of Intel Pentium advertisements. Few people would begin to understand a technical discussion of why the additional on-chip cache memory and denser architecture of the various Pentium computer chips make the machines that use them more desirable. So, Intel simply ran colorful musical whimsy that said Pentium was better and you better have "Intel Inside" your computer. It gave no reasons, no logic, no arguements at all. Just do it because the ads are so entertaining, people fly around and dance to the zippy music, and everything is great if you make sure to buy things from Intel that say Pentium. The advertising worked because people knew nothing about chip design, and competitors such as Advanced Micro Devices did not run colorful entertaining ads on prime time TV. Simply by repetition and by default, Intel gained huge mind share among buyers who didn't have the slightest logical reason for wanting their product, except they heard of it in a happy and suggestive ad package. Fortunately, in this case, the product was good and no one was hurt by being told to buy it, except perhaps that they may have paid more than if AMD or others had offered counter-ads of the same style more quickly. But how many other "everybody says so" situations do we constantly let slip into our own thinking, without knowing why? Always ask why. If you don't get a good answer, maybe there isn't one! Maybe the answer is, someone wants more of your money without going to the trouble of proving any more benefit to you! A. Split moulds open up and expose their 450+ degree interior surface to room temperature air on every cast, which has to distort and warp the hole slightly. They clang shut and cause slight misalignment as there needs to be some tolerance in the pivots, and wear takes place from the first time you use the mould. The split design of a mould insures that you will always have some degree of wear, misalignment, and out-of-roundness as a result of both temperature variation and mechanical mis-alignment. THE SWAGE DIE IS A DIAMOND-LAPPED CAVITY IN A SOLID CYLINDER: IT HAS NO "HALVES" TO MISALIGN. SWAGED BULLETS ARE INHERENTLY MORE ROUND. The mould temperature must vary from molten lead to solid lead on every cast (or you'd pour out the bullet in liquid form!), which means the size of the mould cavity constantly changes with temperature. THE SWAGE DIE RUNS AT ROOM TEMPERATURE, NO HEAT APPLIED: IT STAYS AT A CONSTANT DIAMETER. SWAGED BULLET ARE INHERENTLY CLOSER TO EACH OTHER IN DIAMETER. The cast bullet is compressed only by its own weight (one atmosphere of pressure), which can leave voids and pits and air pockets inside. THE SWAGED BULLET IS FORMED BY COLD-FLOWING LEAD WITH 2,000 OR MORE ATMOSPHERES OF PRESSURE. AIR POCKETS AND VOIDS ARE ELIMINATED. THE SWAGED BULLET IS INHERENTLY BETTER BALANCED. The cast bullet can vary from one to another due to slight differences in alloy because the lead, tin, and antimony can separate slightly as you continue to mix and cast, resulting in different weights, diameters and densities of bullets from one to the next. WITH SWAGING, ONE BULLET IS PRECISELY LIKE THE NEXT. THERE IS NO CHANGE IN ALLOY SINCE ALLOYS ARE NOT REQUIRED TO MAKE NON-FOULING SWAGED BULLETS USING JACKETS, BASE-GUARDS, or GAS CHECKS. ALLOYS CAN BE USED BUT THEY ARE FORMED COLD SO THEY CANNOT SEPARATE. SWAGED BULLETS ARE INHERENTLY MORE CONSISTENT IN WEIGHT AND HARDNESS. These are just a few reasons. There is a book full of other reasons: The Corbin Handbook of Bullet Swaging will explain in detail precisely why swaging produces better bullets than casting. Virtually every factory bullet is swaged. Virtually every benchrest winner uses swaged bullets. (There can always be an exception: try to find it! Then try to repeat it yourself! With swaging, you can make the same bullet anyone else can make, or you can make better ones!) Q. How do you put a jacket on a bullet? A. You don't. You expand a jacket by putting an undersized lead core into it, and then compressing the lead with a punch, so it flows like a thick liquid. The lead transfers high pressure to the jacket from the inside, and pushes the jacket into precise conformity with the inside surface of a diamond-lapped die cavity. You actually MAKE the bullet at that instant, you don't make a bullet out of lead and slip a jacket over it! That is why the lead wire is always so much smaller than the caliber (except for lead bullets). It has to fit inside the jacket, so it must be at least twice the jacket wall thickness smaller than the jacket diameter, which itself is always a few thousands smaller than the caliber you will create. The die itself determines the bullet diameter. The pressure of pushing the lead core outward to fill and expand the jacket, like a balloon skin, is what makes swaged jacketed bullets so precise: the core cannot slip and turn inside the jacket because of the tremendous gripping pressure of the jacket as it trys to spring slightly back to original diameter. When you draw down an existing bullet to smaller size, you can only reduce it about .005 inches before the spring-back defeats you by attempting to go the other direction (larger) when pressure is released. This releases the grip on the core and lets the core fail to spin with the jacket when rifling is engaged, resulting in poor stabilization and poor accuracy. Swaging, which works by expanding the diameter, tightens the grip of core and jacket. Drawing down makes the jacket loose if it exceeds the elasticity of the jacket (.005-inches is a good approximation for most jackets). Q. Can I use my reloading press for swaging? A. Yes, Corbin makes the Pro-Swage dies and other type -R dies for the reloading press. Some weights, shapes, and calibers or styles are not available for a reloading press. Most paper-patched or pistol bullets with SWC shoulder (and almost any nose shape) can be made with the Pro-Swage dies in your sturdy slotted ram 7/8-14 threaded reloader (like an RCBS Rochchucker or Pacific MultiPower). To find out which bullets are suitable for reloading presses, read the Corbin Handbook of Swaging. It will explain in detail what kind of bullets can be made without using an actual bullet swaging press (which is far more precise, fast and powerful than any reloading regardless of size, since a reloader needs 4 inch travel and a swage press can cut that in half to 2 inches, doubling the power automatically with the same lever system). There are four other main features of swaging presses that make them better choices than reloading presses, plus the fact that most swaging dies are designed to work in a swaging press ram, not a reloading press head, so gravity works with you instead of fighting you (as it would in the reloading press). Q. What about those who say swage dies with a shoulder and threaded shank are weak? A. Just think about it. This arguement is based on the false assumption that the pressure inside the die is applied to the thread shank area as well as to the full diameter area. The internal punch in Corbin dies stops the pressure before it reaches the shank, keeping it within the heavy part of the die. If a swage die is made all one diameter and threaded on the OD, the threads must take all of the force of driving the component into the die as it expands, except for the component of force that acts directly in line with the ram against the bottom (internal) punch. By turning down a shank portion on the end of the die, and threading this shank only, a shoulder is created between full diameter, and the thread diameter. This shoulder is a full half inch on Corbin -H dies, and 3/8-inch on Corbin -S dies. The area under this shoulder bears directly on the top of the hardened ram of the Corbin press, and takes all the stress off the threads on the swaging stroke. It might seem to a non-toolmaker that making the entire die larger would result in a stronger die, but in actual fact, it results in putting more stress on the threads of both the die, and the press, and can create stress fractures in the threads. By making sure that all the actual work is done in the full diameter section of the die, and that the threaded shank only serves to guide the internal punch, with no internal pressure against that portion, the extra work put into turning a shank and shoulder on the die, and threading only this portion, pays off in a die that takes the stress on a solid shoulder rather than passing it to the threads. Don't be fooled by manufacturing shortcuts disguised and presented as "features" by people who either don't know how to do it right, or would rather not put that much work into your dies. |
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THANK YOU for your interest in bullet swaging!
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Answers.txt
