Learning to cast quality bullets is an important aspect of black powder cartridge shooting. A bullet mould is like a lawn mower-expect problems with it and you won’t be surprised or disappointed. Almost any experienced bullet caster can teach a novice how to cast match quality bullets in a relatively short period of time; however, teaching someone how to troubleshoot for all the possible things that can go wrong with a mould can be an unending task. One thing is for sure, if you have never cast bullets before you will need the help and guidance from someone who has, and the same goes for trouble shooting mould problems. A healthy dose of bullet casting experience and a methodical approach to determining problems are required.
  Some who are new to casting might not even know what a quality bullet should look like; I certainly didn’t. When I first became involved in silhouette competition over 20 years ago all of the bullets I cast had slightly rounded bases. For me, this was such a normal occurrence that I thought they were supposed to be that way. I am embarrassed to admit that I shot rounded-base bullets for over six months before someone finally pointed out to me that this was NOT the way they should look. Back then, my casting technique was so poor that not a single flat-based bullet fell from my bullet mould, and my scores were reflective of the substandard bullets I cast. At my first ever silhouette match at the national championships at Raton in 1998 I hit a grand total of six animals. And even though I have cast thousands of bullets since that time, I am still not immune to the occasional bullet mould related problem. But unlike before, I always check my moulds for problems before and during a casting session. Knowing what to look for and being consistently vigilant in anticipating problems is now part of my casting routine.
  Several of us have written articles for this magazine on the “how-to’s” of bullet casting, so I will not delve into that here. Rather, I will discuss and offer solutions for some of the obvious and not so obvious problems that are commonly encountered when casting bullets.
  Wrinkled or improperly filled bullets will more than likely be the first problem encountered by the novice bullet caster. By improperly filled, I am also referring to bullets that have rounded bases. This problem is really not all that difficult to diagnose or solve. Many of the problems encountered while casting, including improperly filled bullets, can generally be attributed to one of seven of the following factors: 1) the mould is too cold, 2) the lead is not at the proper temperature, 3) the lead was improperly introduced into the mould, 4) the air cannot escape from the mould when lead is introduced, 5) lead deposits have accumulated on the face of the mould, 6) mould pins are out of adjustment and, 7) oil or mould prep residue may be present in the mould cavity. Rather than just listing seven causes for improperly filled bullets, I will go into more detail.
  Beginning a casting session with a cold bullet mould always results in poorly filled bullets, and only when enough bullets are cast to raise the temperature of the bullet mould to the ideal casting temperature will the mould actually be ready. It seems only logical that molten lead poured into a mould cavity would heat the mould to ideal casting temperature fairly quickly; however, this is not the case. Usually, forty or more bullets must be cast and rejected before the first bullet worthy of shooting falls from the mould. This can be a cyclic problem, especially for those who have limited capacity lead pots. By cyclic, I mean, by the time the mould has reached ideal casting temperature it is time to add more lead. While waiting for the added lead to melt, the mould cools back down. Thus many more bullets must be cast and rejected before the first decent bullets are produced. This is usually the first source of frustration for those trying to learn how to cast bullets.
  Obviously, the solution to the cold mould problem is to preheat the mould before casting begins. A hot plate works well for preheating a bullet mould as does placing the mould on the rim of the lead pot. With either method, it is important to heat the mould gradually. I use an electric hot plate for preheating moulds, and I always begin at the lowest temperature setting and increase the temperature gradually until the mould is at the ideal temperature to cast perfect bullets. Finding the proper bullet mould temperature as it relates to the temperature setting on the hot plate is found by trial and error. On my hotplate, however, it has never been necessary to set the temperature any higher than the medium setting. At no time will the hot plate heating coils glow red during preheating of the mould. If the bullet mould is placed on the rim of the lead pot, do so when the lead pot is first turned on. This will allow the mould to heat up gradually as the lead in the pot melts. Perfectly filled bullets will drop from my preheated mould after only six to eight bullets are cast. It makes absolutely no sense to consume 30 to 40 percent of the lead in your casting pot by casting and rejecting bullets before the mould reaches the temperature necessary to cast the first well formed bullet. A double layer of aluminum foil placed over the mould as it heats up, aids in achieving uniform heating of the mould as well.

Pre-heating a mould on an electric hot plate

  Plunging a cold bullet mould into hot lead is not the correct way to heat up a bullet mould. I do not know who came up with this idea, but the concept seems to persist even today. This is not only dangerous but it is also “double dog” stupid. Dunking a cold bullet mould into molten lead can cause lead to splatter out of the lead pot onto anyone standing nearby. If you ever wondered how it feels to be hit with a piece of artillery shrapnel, this is one sure way to find out. One thing for sure, the molten lead is going to burn your skin a lot longer than you can stand for it to burn. On the other hand, rapid or non-uniform heating can also result in a warped bullet mould. It is for this reason that I do not recommend heating a bullet mould with a torch. Once again, heating a mould too quickly or unevenly can cause the mould blocks to warp.
  Maintaining a uniform mould temperature from the start of the casting session to the end is the key to achieving uniform bullet weights. When a uniform mould temperature is achieved it is not uncommon for 95% of the bullets cast in a session to fall into a mean weight range of plus 0.2 grains to minus 0.2 grains. With most electric pots, the temperature of the lead increases as the lead is removed. This is especially noticeable once lead levels drop to around 50% of the volume of the pot. As the temperature of the lead increases there is a corresponding increase in mould temperature, which results in slightly heavier bullets. These bullets will shoot okay; however, for those of us who are trying to achieve uniformity of bullet weights, this can be a source of aggravation. I refill my casting pot as the lead level is approximately 50 percent depleted. My Waage pot will hold adequate lead to cast about 80 bullets by the time the pot is half empty. If I intend to continue casting, the bullet mould is returned to the hot plate and covered with tin foil until the lead reaches proper casting temperature.
  It goes without saying that the temperature of the bullet mould and the temperature of the lead go hand in hand. The ideal casting temperature for lead will be somewhere between 650 and 750 degrees, depending on where you live and your elevation above sea level. Regardless of where you live, it should not be necessary to heat lead above 750 degrees to cast good bullets. As a side note, I read somewhere that when lead reaches a temperature of 800 degrees or more, the amount of toxic fumes produced increases dramatically.
  Achieving an optimum lead temperature is a “no-brainer”, as is maintaining a uniform mould and lead temperature from the beginning to the end of a casting session. You may have not thought about it this way, but the temperature of the bullet mould must be less than that of the lead for bullets to solidify. Although I have never heard of anyone heating a mould so hot that lead would not solidify, if bullets are cast at too fast a pace, the mould temperature increases and the spread in bullet weights will naturally be greater. Other problems besides bullet weight uniformity can be expected when casting from a mould that is too hot.
  If you begin to notice an arc of lead across the top of the bullet mould that corresponds to the hole in the sprue plate, adequate time is not being allowed for the lead to solidify before the sprue is cut. The hotter the bullet mould, the longer it takes for the lead to solidify. A sprue that is cut before the lead is completely solidified will result in molten lead being deposited on top of the mould blocks. This deposit of lead can gradually build up and increase the distance between the top of the bullet mould and the bottom of the sprue plate. When this occurs, one of two problems can result. The first is a “finned” based bullet and the other is a raised-base bullet. Often the novice caster will attempt to correct such a problem by tightening the sprue plate. If the mould was casting good bullets at the beginning of the casting session, tightening the sprue plate is not the answer. The correct course of action would be to remove the smeared lead from the top of the mould with a lead cloth and then cast at a slower cadence or turn down the temperature of the lead pot.
  Other problems such as “torn sprue holes” can also result if a proper casting cadence is not maintained. To avoid this problem, cast at a cadence that is slow enough to allow the lead to cool adequately before the sprue is cut, and then cut the sprue away from the bullet slowly and deliberately. When cutting sprues, I place the front edge of the mould against my bench (for support) and then use a mallet to push the sprue plate slowly away from the mould. The ideal bullet will have a flat and smooth base with no torn out sprue holes.

Perfectly flat bullet base (left), torn sprue (middle), and a bullet with a raised base (right)

  Returning sprues and rejected bullets back to the lead pot as each bullet is cast is a practice I avoid because this can cause the lead temperature to fluctuate or it can affect the temperature of the bullet mould. Such a practice can result in variable
bullet weights.
  Some of the more subtle problems that can occur with a bullet mould involve the gradual build up of lead on the face of the mould. This happens when small deposits or flecks of lead make their way onto the face of the bullet mould. Out-of-round bullets or finned bullets can result when this happens.

Example of a “finned” bullet

  Constantly check for flecks of lead deposits on the bottom or face of the bullet mould. If lead flecks are found, they should immediately be removed by using lead cloth wrapped around a “chisel pointed” hardwood stick.
  It is important to understand that these lead flecks make their way to the mould during casting. However, if you are casting properly, it is somewhat of an unavoidable problem. To produce bullets with perfect bases, it is necessary to fill the mould with enough lead that it overflows from the mould leaving a dime to nickel-sized lead puddle on top of the sprue plate. In doing so, often the excess lead will dribble back into the lead pot and small specks of lead will splash up and land on the base of the mould. If the lead specks happen to land on the seam where the two mould halves join, these small flecks of lead can melt and migrate between the two mould halves. An almost imperceptible gap between the two mould halves results and bullets cast from such a mould have noses that are “out of round” or non-concentric to the axis of the bullet. Even only one half to one thousandths of a gap between the two mould faces can affect bullet concentricity enough to destroy accuracy. If a noticeable deterioration in accuracy of a proven load develops, this is one of the first places I look when attempting to diagnose the source of the problem. 

Lead cloth and “chisel pointed” hardwood stick

  Trouble shooting, by checking for gaps between the two mould halves, should always be done before and during casting. Before preheating a bullet mould, I always inspect for flecks of lead on the mould faces themselves and also on the base of the mould. If I discover flecks, I use a lead cloth wrapped in a chisel shaped hardwood stick to remove these small lead deposits. Visually checking for gaps between the two mould halves is easy. With the sprue plate swung out of the way, I hold the mould up to the light and look into the mould’s cavity. You should not be able to see any light between the two mould cavities. If you do, lead deposits on the face of the mould could be one source of the problem.

Checking for gaps between mould halves

  While on the topic of inspecting for gaps between the two mould faces, it is important to realize specks of lead on the face of the bullet mould is not the only thing that can cause a gap between the two mould halves. Most notably, the pins that serve to align the two mould halves can be out of adjustment and prevent the mould from closing completely. I have bought more than one custom bullet mould that came from the maker with improperly adjusted pins. When purchasing a new mould, this is the first thing you should check. Open and close the mould several times when checking for a gap between the mould halves on a new bullet mould. If a gap is found, with the mould blocks firmly inserted and secured to mould handles, turn the mould where the side faces up and rap the mould with a mallet to force the mould closed. If upon re-inspection no light is seen between the two halves, then the culprit of the problem is improper pin adjustment. If pin adjustment is the source of the problem, I suggest you contact the maker of the bullet mould and ask for the proper procedures to correct the problem. There are usually three pins on most custom moulds, and these pins need to be adjusted precisely and in the proper sequence to achieve good bullets. I advise against adjusting these pins yourself unless you know exactly what you are doing. If you do this incorrectly and start casting bullets, it won’t take long to mess up your mould.
  Sprue plate adjustment is also critical to achieving properly cast bullets. The novice caster tends to over tighten the sprue plate. When the mould is empty and at casting temperature, the sprue plate should pivot freely on the sprue screw and fall away from the mould. Conversely, if the sprue plate is too loose, lead will flow between the mould and the sprue plate and form winged base bullets. Trial and error will achieve the proper setting in most cases.
I use a straight edge to insure that the part of the sprue plate that mates up with the top of the mould is perfectly flat. I have on occasion used a stone to flatten or square the bottom of the sprue plate. If a stone is employed, use a fine stone so the bottom of the sprue plate is smooth and without ridges or grooves. It should go without saying- but I am going to say it anyway- do not even think about stoning the top of the bullet mould.
  Although using the proper method for introducing lead into a bullet mould is more of a casting technique rather than a physical problem with the mould, this is a crucial step in achieving well-formed bullets. And, this is generally one of the last things a novice bullet caster learns. Here is the sequence. Fill the mould ladle with lead and pour off a small amount. With the mould turned with the sprue hole facing east, mate the ladle hole to the sprue plate hole. Turn the mould and the ladle in unison so that the top of the mould is straight up or facing north. Once the mould fills with lead, remove the ladle and enough lead to pour out of the ladle on top of the sprue plate to form a dime to nickel-sized puddle on top of the sprue plate. Once it is visually apparent that the lead has solidified, slowly count to ten. Now push the sprue plate with a mallet to cut the sprue. Using any other ladle-to-mould technique will result in a high percentage of bullets cast with rounded bases. Learning this technique is a little awkward at first, but it must be learned in order to achieve quality cast bullets.

Steve Brooks vented sprue plate

  In item number four of the introduction, it was mentioned that the inability of air to escape from the mould when lead was being introduced was a potential cause for improperly filled bullets. This can be a persistent problem for even the most experienced bullet caster. Vented sprue plates (sold by Steve Brooks for his moulds) have gone a long way to solving this problem. Some casters file a groove in the nose of their ladle to allow air to escape.
  While we are on the subject of pouring techniques, have you ever cast bullets where one side of the bullet’s nose had a slightly frosted appearance while the other side was shiny? This can be remedied by inverting the mould and ladle more slowly while pouring lead into the mould. Earlier I mentioned that oil or mould prep deposits in bullet moulds can cause incompletely formed bullets. If oil or grease deposits are the source of a casting problem, it is usually because these products were used when the mould is put away for storage.
  Even with a thorough degreasing by using such products as Gun Scrubber and then preheating the mould on a hot plate, many bullets will have to be cast and discarded before the first decent bullet will be cast. I never apply oil to the inside of my bullet moulds. I put them away dry with the last cast bullet remaining in the mould cavity. Now, I live in an area of the county with low humidity, so if this is not good advice for those who live in the more humid regions of the country, please write in and set the record straight.
  Also, I have never discovered the necessity of commercially available mould prep products, and therefore, not only do I not use them, I recommend that they not be used. They are the perfect solution to a non-existent problem in my opinion. They tend to have the same affect on the mould as does oil deposits. If however, some of you feel I am wrong in my assessment, please write the editor of this magazine and express an opinion and offer advice.

Using pressure on the corner of the mould block to separate mould halves

  Lastly, if you have mould “chatter marks” on your bullets, you need to revise your technique for opening the mould. It should not be necessary to bang around on the mould handles to free the bullet from the mould. Excessive banging before one side of the mould clears the bullet results in these chatter marks. Once again this is usually not really a mould related problem, but rather a problem with technique. Once the sprue is cut, use your mallet to push on one corner of the mould to separate the mould halves. By doing this, you should be able to swing one mould half away from the bullet, and this should allow the bullet to fall freely from the other half. Sometimes it is necessary to additionally lightly tap on the mould handle to free the bullet from the mould half.
It is also necessary to understand that both halves of the mould blocks must swing freely on each side of the mould’s handle. This fit should not be stiff or so tight that the mould half binds when secured to the handle. On more than one occasion, it has been necessary to draw file the part of the mould handle that slips into the side of the mould in order to achieve a proper fit.
Well, there you have it. Hopefully, one of these tips will solve or head off a potential casting problem or serve as a clue to why reduced accuracy was experienced from a previously proven load. Oh… and good luck with the lawn mower.