Lead projectiles have been a part of firearms since their invention. It is almost the perfect material for projectiles, almost. It’s malleability, one of the attributes that makes lead ideal for projectiles also can create problems. As the lead projectile is swaged into the bore during firing, it has a tenancy to smear and leave a trace of itself behind. These smears are collectively known as leading, and can accumulate.
Leading can have a detrimental affect on accuracy, and in the worse cases can lead to high pressures. Leading can be difficult to remove from a bore, as the lead grips tightly to the peaks and valleys left behind from machining. There are several different types of cleaners, and techniques that can be used to remove lead from a barrel, but they all require considerable amounts of elbow grease.
There are lot of misconceptions and misinformation when it comes to what causes leading. Many will make the claim that bullets with any exposed lead, even those that are otherwise jacketed, will lead the bore. This is simply not true. There are a variety of factors that are contributes to whether a lead bullet will lead the barrel or not. A few of these factors are listed below;
- Bullet to bore fit
- Lead Hardness (Alloy)
- In Bore Velocity
- Lubrication or Coating
- Bore surface roughness
- Rifling type (Land & Groove or Polygonal)
It is beyond the scope of this write up to cover all the ways to eliminate leading, only to say that it is a possibility and one of the reasons we either lubricate or coat a bullet is to prevent leading from occurring.
What is the Typical Solution?
Lead bullets are not as common as they once were. Nearly all commercial ammunition today is sold with jacketed bullets. The brass or copper jacket contains the lead, and eliminate lead fouling, allowing for more reliable feeding and higher velocities. The lead bullets that are sold, are typically lubricated, either with a waxy finish over all the bullet, or by thin groves filled with wax. (See Photo Below)
Typically bullet lube is some sort of wax. It provides a barrier between the lead and the bore, preventing the lead from adhering to the bore. The down side to lubricated bullets is they tend to produce a lot of smoke when fired. This is is due to the wax and not the bullet itself. For this reason, cast bullets are frowned on indoor shooting ranges.
If you have ever messed with Lee Alox, you’ll know that it dries to a slightly tacky finish. This finish gets over everything, your dies, your ammo can, and your hands. I have taken to adding some motor mica to the bullets to try and help reduce the tackiness of the bullets. It can be quite smokey when it is shot. While it is simple and cheap to apply, it does have it’s draw backs.
I have shot thousands of cast bullets lubricated with either Lee Alox, or a lubrisized bullet with fantastic results. I am sure there have been billions of bullets made buy hobbyist and commercial enterprises alike. So there is nothing that is inherently wrong with these lubricants. However in the last 15 years there have been some new coatings on the market that provide lubrication, and add a splash of color to the mix.
Alternate Coatings
The alternate coatings out there are divided into two primary categories. Epoxy coatings and Powder coatings. The epoxy coating is typically a two part coating that is mixed and applied to the bullet prior to baking it onto the bullet. Powder coatings are typically a vinyl coating that is a single part powder. This is applied to the bullet and it is baked on.
Several years ago I experimented with using Harbor Freight Powder Coating and a small oven. I had limited success, but was not overly impressed with the process. So I looked at the available epoxy coatings and purchased some Hi-Tek Bullet Coating.
(There are coatings such as Hex Boron Nitride or Molybdenum which are lubricants but are not typically used for lead bullets)
Hi-Tek Bullet Coating Application
Hi Tek Bullet Coating is either a two part epoxy if you purchase the powder, or a three part system if you purchase the liquid (Acetone or MEK is required for thinning). I purchased both with the intent to see which one I liked more. For this application we stuck with the liquid product.
The instructions warn that this process might take a few tries to get right, so to be patient. I would agree with that assessment. If this is your first time, hopefully you can read over this write up in combination with the instructions and learn from some of my mistakes.
As previously mentioned this coating requires that you bake it on so you will need some sort of oven, preferably not your wife’s. You don’t want to taste the fumes in your meatloaf, trust me. When it says an oven that holds temperature fairly well, it should say “Have a way to verify oven temp” . Oven baking temp, and bake duration are critical criteria.
You’ll want some space, I’d say at least a four or five feet of table space in addition to the space occupied by the oven. so you can spread things out to dry, and cool. The instructions call for wire mesh racks but I found parchment paper and paper towels worked well too.
You’ll want some mixing containers. The instructions suggest a 2.5 gallon pail, but I used a yogurt and cottage cheese container to do my coating in. I also used half of my yogurt container to “meter out” how many bullets were in a batch. The instructions say about 1ml per pound of bullets. I figured I did about 2lbs of bullets per batch and used 10ml of coating to coat them.
In terms of mixing ratios, the instructions say 5 parts color, 5-7 parts acetone, and 1 part catalyst. (5:5:1) This coating seemed to work better if I used more acetone, a 5:7:1 covered and dried better then the 5:5:1. However I felt like I needed to add more to get complete coverage then what the instructions said (Hence 10ml per 2lbs rather then 1ml per lb).
This process requires good ventilation, the coating produces smoke when you bake to coating on, and you are working with acetone which flashes off and creates fumes. An open garage door and some fans are not a bad idea.
With ventilation comes temperature control. One of my mistakes is likely weather related, as the ambient temperature was around 40 degrees. Perfect for casting, but it was not warm enough to flash off the acetone. I believe this resulted in some of my early failures as I baked the bullets prior to them being completely dry.
To remedy this I used a brass drier, which is a re purposed food dehydrator. This allowed me to preheat the coated bullets and drive off as much acetone I could before baking.
Mixing It Up
For those of (like me) who are not chemists and are not use to measuring things out by “Parts” it is fairly simple. Add up the total of parts ( In the 5:5:1 example it is 11) then divide the individual parts by the sum, multiply by 100 to get the percentage.
5/11 = .45*100 = 45%
If we are making 250ml of the mix, then we will want to take the 45% and multiply it by 250. Thus we get 113.64ml we round up to get 114ml.
Thus if we wanted to do 250ml our5:5:1 mix is as follows.
114ml of color
114ml of Acetone
23ml of catalyst
I include that example, as it was not obvious to me and I was scratching my head for some time trying to figure out. I hope it is helpful for those who, like me, don’t mix paint on a regular basis. While I used the 5:5:1 in the example, I found that 5:7:1 ratio worked better, and I have seen some that say that the 5:9:1 works for them.
It is important to remember this isn’t so much a paint, as it is a stain. It will go on very thin, and the color will develop some in the oven. Subsequent thin coats will add the color to the bullets. When I first pullet my bullets from the oven after that first coat, I was a little under whelmed.
Coating
The oven limited my batch size. I measure out the batches by what I could comfortably fit on the tiny tray. Coating is done by tumbling the bullets. I’ve done this countless times with Lee Alox, so I have a bit of a process where transfer the bullets between two containers.
It is important that you don’t over tumble the coating. The acetone evaporates off, the coating becomes tacky, and tumbling a tacky coating imparts a rough surface texture to the bullet. Once this stuff is tacky, its thick and doesn’t have any kind of self leveling property that come coatings have. The roughness will not bake out.
I tumbled until I could visually see that the bullets had a fairly even coat, and then laid them out on the parchment to dry.
The first layer is the vital layer as it adheres to the lead substrate. All other layers adhere to that first layer. If the first layer is weak it doesn’t matter how many layers you use you’ll still get flaking.
The Drying Period
The instructions say that it can take as short as 30 minutes to as long as 24hrs for the coating to dry prior to baking. It’s all dependent on the ambient humidity, the temperature, and the ratios used. My first few batches I let room dry at roughly 40 degs for about 30 minutes, prior to baking.
I think this was my mistake. I haven’t figured out how to tell when the bullets are dry. They are dry to the touch, not tacky, within ten or fifteen minutes. However if you stick them in the oven they bubble up. The bubbles are caused by the acetone flashing off in the oven. They interfere with the expoy coat bonding to the lead, and this will cause flaking later on (as I found out).
People had mentioned they would coat the bullets and then take a try and set it on the oven to preheat them to aid in flashing off the last bit of Acetone. I decided to go one step further an used a food dehydrator turned brass dryer.
If I was in the summer, where it gets to 100 degrees, this preheat would probably not be needed. However it seemed to work for me to get me through a couple chilly spring days.
Baking
What isn’t really explained is that the oven is a pretty important part of this process. For those who do projects on a budget you might be tempted to do what I did. Pick up a toaster oven from goodwill. This likely made my experience a little more difficult then it needed to be.
The oven tended to “Overbake” the first few batches of bullets I did. Even though I felt like I was hitting that 400 deg target temp, the bullets came out pretty dark. This in combination with the incomplete drying is likely what led to the failures of the first couple batches.
I know what the instructions say, but I found that for this oven, if I allowed it to bake about 8 minutes and let it reach a peak temperature of about 350 degrees I got good results. If I tried to go hotter or longer my bullets would come out quite yellow and lose all other colors. Over baking can also degrade the adhesion., resulting in flaking.
In all cases the bullets smoked some. I am still not sure if that’s a good thing or not. Maybe if I went to a lower peak temperature, I wouldn’t get the smoke but the epoxy also might not cure. So for the time being I take the smoke as a good thing.
Testing
There are a few tests to do in order to determine if you have a good first coating. The first is the acetone test. What you are doing is seeing if the acetone will redissolve the coating. I take and put some on a white paper towel and then wipe the bullet with it. No color should transfer over to the towel. Should you fail this test, pop the bullets back in the oven and bake for a bit longer or check the temperature of the oven, in my case someone unplugged the oven.
The acetone test is a pretty simple test, the next test requires you to destroy a bullet. One of the main selling points of this product is how well is adheres to the lead. The coating shouldn’t flake off even under extreme pressure including when impacting a target. We can simulated this by smacking it with a hammer, or squeezing it with pliers.
When you are me, sometimes you get stubborn and say things like, “Well, I can live with a little flaking if they pass through the sizing die ok.”
They recommend you test after the first coat instead of waiting until you’ve done all of your coats. I didn’t do that with my first batch as I wanted to work through a process without fussing over all the details. When I saw that I was having a flaking issue, I went to the internet. CastBoolits.com is a wealth of information if you take the time to do some reading.
How Many Coats?
I started off doing three coats on my first couple batches, but I then switched to doing just two coats for the rest. The reason I did three coats on the first batches was to try and get the color, but I determined that the color was fading because the temperature was too high and the bake time was too long.
I’ve also read that too many coats can contribute to flaking. So I decided to try 2 coats while trying a few things to improve the process. They held up well during sizing, and besides a slight polish to the coating its hard to tell sized bullets from unaltered ones.
Final Thoughts
Overall I am satisfied. As I stated at the beginning of the adventure, the instructions warn you need to be willing to fail and try again to develop a good process. Unlike other coatings or lubricates there is an involved process with Hi-Tek coatings. There are several variables that have to be accounted for in order to get good adhesion and good results.
With that said, once you get the process figured out, it goes pretty quick. This is my first run, and I am close to getting “consumer grade results” but there is still some work I need to do to get an even coating. It’s good enough for me to shoot, but not something I am ready to sell (If I were to do that). As with everything in this hobby, your experience may depend on the quality of tools you purchase, for example had I purchased a better oven, I would have been able to load larger batches and likely messed around less with the temperature.
Another potential issued is sizing the bullet. Lubrication is only one of several variables that help control leading in the bore. A properly sized bullet, by all indications, is the most important criteria. I have long used the Lee Push through dies to size the cases lubed with Lee Alox. These push through dies are designed to have lube on the bullets, but in trying to size these Hi-Tek coated bullets, the forces were a little higher, indicating the coefficient of friction on these bullets is higher then a Lee Alox tumbled lubed bullet. This sometimes created defects and flashing around the base of the bullet which is undesirable. I’ll be doing a follow up write up on hole I solve this issue.
For those who are used to the traditional methods of bullet lube and sizing, I would give this a try. It is a bit more time consuming and involved of a process, but in the end I think it has the potential of producing a better result. I have read the powder version is easier to mix and it doesn’t require a hazardous materials shipping charge to ship, so consider that. When I dip into my powdered product, I’ll do a short write up on that.