Canadian Airgun Forum

Part 1: Background

The story started several years ago when I bought a non-pal 9mm airgun carbine and a Crosman 1100 Trapmaster (topic69050.html).

After experimenting with different types of projectiles (wax, wood, plastic tubing tipped with hot glue) that were not giving good results, I finally have purchased a mold for casting .380 lead balls for the Crosman 1100 Trapmaster and, later, another .350 mold for the Rob Sterne’s 9mm airgun carbine. This allowed me to be able to recycle the used lead pellets I had accumulated over time.



Since most of my air guns are either .177 or .22, I was also interested in obtaining the appropriate molds for them. No need to say that neither of the calibres are easy to find. Some people use swaging but this was not what I was looking for.

In my job, before I retired, I had access to a CNC mill and I decided to try to make a .22 mold myself. They were more like some sort of slugs than pellets but it worked.

Following that experience, to prove that it was possible, I decided to make another .22 mold but this time in a very artisanal way using only basic tools like bandsaw, drill press and files. Again, the projectile was shaped as a waisted slug and it worked too.
The picture below shows both molds.



Eventually a commercial pellet mold was available from Noe in the U.S. in calibre .22, there was also some plan to make a .177 version but it never happened.

I bought one of their .22 molds which are expensive but very well made and I am satisfied with my purchase. The mold allows the casting of a solid pellet as well as different depths for the cavity in the skirt.
This is the Noe .22 mold.



It was just disappointing that the.177 version was not manufactured by Noe and I continued looking on the web if anybody else tried to make one.

R-Gun Pete

Part 2: The beginning of the project – Making the cutters

Not long after retirement, I bought a mini mill and a mini lathe and I have been learning how to use them since then.

Last year I worked on a couple of ambitious projects and I thought that I had put some ideas in my 2023 folder on my computer for the reopening of the shop this Spring.

I guess I misplaced those ideas because the folder was empty.

Since I had nothing planned I decided that it might be a good time to revisit the project of making a .177 pellet mold.

This would provide me with a new challenge like making some custom cutting tools.

I remembered that, last year, a friend gave a few pieces of high speed steel and a piece of drill stock rod. After having the shop closed for the winter, my old brain couldn’t remember where the piece of drill stock rod was.

When I came across a small shiny round bar, I thought it was the drill stock rod. Trying to cut it on the lathe, I quickly discovered that it wasn’t.

This was high speed steel and the only way to shape it would be with a grinder. As I didn’t want this type of dust in my lathe, I clamped my hand drill in my workmate outside, and used my angle grinder to shape the rotating part close to .177 in diameter. For the neck area and the flared skirt, I switched to the Dremel tool.

In the meantime, I found the drill stock rod I was looking for and machined another pellet blank with the lathe. When I took my last roughing cut, I thought there would be enough material left for finishing, but I ended up undersized at .175”.
The picture shows both blanks



Anyway at that stage it was only experimentation because I didn’t even know if I would be able to make cutters from the blanks.

The idea was to transform the blank into a “D” bit single flute cutter by getting a flat surface at the centre line.

For the HSS blank, the bench grinder was used. Then the drill stock blank was machined on the mill and heat treated to harden it. My friend told me that I would need a relief close to the cutting edge but the shape was so small that I couldn’t figure how to do it, so I just decided to leave it as it is.

At this point, I was ready to test the cutters. I guess I was a bit too eager to proceed and just picked two small pieces of aluminum having two matching edges.

With the HSS pellet shaped bit I cut one side and the result looked good, so I lined up the other piece in the vise and cut the opposite cavity. The machining test was conclusive.

I was interested to see some result so, with a piece of masking tape, I taped both plates together aligning the reference edges to form a mold, then I used a hot glue gun to inject liquid plastic in the cavity.

The blob outside the mold was shaved with an X-acto knife and since I had applied a thin coat of Vaseline to the mold cavities, when I opened it the plastic pellet fell off.

This picture shows the cutter, the mold and several cast pellets.



The process was repeated with the other cutter but this time the aluminum plates were prepared more carefully and locating pins were added.

This picture shows the second cutter, the mold and several cast pellets.



Now that I have some castings from both molds it is time for some tests. It is difficult to measure the exact dimensions on the plastic pellets because the material is softer than lead, consequently I am not sure if they are undersized or not.

R-Gun Pete

Part 3: Testing the cast plastic pellets

I have an old Webley Junior that is so underpowered that, unless a regular .177 Crosman pellet is pushed through the barrel to be resized first, there is a big chance that it wouldn’t shoot it. If the plastic pellet fell through that barrel then it was definitely undersized.

Luckily it sled in easily and stayed there, I decided that it was a good omen. I had a sheet of letter paper in my trap and when I shot the airgun, expecting to get a bouncing projectile, to my surprise a hole appeared. After several reiterations with both types of plastic pellets, I had multiple holes in my sheet of paper.

I was thinking of trying with a different airgun which would be more powerful but I didn’t want a springer in case the plastic projectiles were too light. My Gamo Compact was chosen because it is a single stroke pneumatic.

Again both types of pellets didn’t fall through the barrel and were able to punch holes in the paper from a longer distance than the Webley Junior.

These are the airguns used for the tests



My next test, with the Gamo Compact, was to shoot at pop cans from about 10 feet. I started with a pellet made from the second mold (cut with the drill stock rod) and it punched through both sides of the can. I repeated the experience a second time with the same result. I was expecting the same thing when I shot a pellet from the first mold (cut with the HSS) but to my surprise it simply bounced off. The second try did the same thing.

This picture shows the damages to the cans.



Knowing that the plastic pellets could punch paper and damage cans, the next logical step would be to check accuracy. For that part, I switched to my CZ 200T pcp rifle.

I started again with the plastic pellet from the second mold and I shot the same pellet over and over from 31 feet. I lost count but it is certainly between 30 and 40 shots on the same target. All the shots were taken standing and the rifle hand held. I was really surprised and pleased by the result. The rectangular border on the target measures 3.75”x5” and the black bullseye is 1” in diameter.

In the picture, the used pellet is on the left and an unblemished one is on the right.



Feeling cocky, I shot the plastic pellet from the first mold, from the same distance and at the same size of target and got a reality check. NO HOLE!!!

After a few shots, all misses, I needed a different strategy. I replaced the target by a blank letter size sheet. NO HOLE!!!

I moved to 10 feet from the target and, wow, at least I got a hole in the sheet but not even close to where I was aiming.

It was time to look closely at those pellets. Because I was in a hurry to start cutting when I made the first mold, I was only relying on two edges for alignment. Closer examination revealed a misalignment of both halves of the head. That certainly doesn’t help with accuracy.

R-Gun Pete

Part 4: Modifying the first mold, redoing the test and what are the conclusions.

By placing the cutter in the mold, I was able to realign it the way it should and after taping it with a piece of masking tape, I drilled two holes for locating pins.

When I made new pellets from the corrected mold I discovered that not all hot glues are made equal. I had a very long cylinder of glue when I started casting the first versions but it was nearly used up by the time I was done. So for this new batch I inserted a short one from another bag but quickly realized that it was way stickier than the other one. Removing the pellet from the mold was not easy and they got distorted.

Finally, with a combination of lubricant and finding another piece from the original glue I was able to complete the casting of a new series.

This is the difference between the first generation and the second of the pellets from the first mold.



I was hoping that the accuracy would be better with this version than with the other.

Unfortunately with the CZ 200T the spread was still too large so I decided to check if it could be improved if I used the Daisy 853C.

It was definitely better with the 853 than the CZ but the distance had to be reduced to 20 feet and even then, after 10 shots I just gave up.

This is the result on the same size of target as previously. The pellet used in the shooting is on the left and a pristine one on the right. The corrected mold is also in the picture.



In conclusion, it seems that the plastic pellets from the second mold are superior to the ones from the first. It is difficult to know if the same behaviour would persist if they were cast in lead.

My intent when I started my project was to make a five cavities mold to cast lead pellets. I have a set of handle that I would remove from this .380 mold and reassign to the .177 if I can successfully make a good design.



At this point I am a bit stuck. Before making a final mold, I am not sure if I should machine another cutter with a better design than what I did.

What would be a best design in respect to the proportions of an ideal pellet?

From what I can extrapolate from this experience, it seems that smaller head to skirt ratio works best. Is true? I don’t know.

It also seems that the neck shouldn’t be too small to avoid casting problem. I had several rejected pellets with the corrected first mold when making the new batch.

Another question would be about which part of the pellet should be cut by the sprue plate. I made mine with the tail being cut off but would it be better to have the nose instead?

Whatever the orientation, I know that it will be a solid pellet without the hollowed skirt because adding pins like the Noe .22 mold would be way too difficult for me.

For the time being, at least, I have one plastic alternative to lead pellet that is good enough for informal plinking, which in itself is not a bad outcome at all.

If you have some suggestions I will be happy to receive them.

Thanks.

R-Gun Pete

Awesome experimentation and machining work there R-GP.
Ultimately, I think the cost and effort to cast your own .177 diabolo pellets is going to be too much for too little. It was a neat experiment, but stick to paying real hard after tax $ for commercial .177 pellets and recycle that lead into .22 and higher cal slugs and round balls.

_________________

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Age quod Agis, et semper ubi sub ubi.

Although casting can be done, i think its too much time consuming to melt material and pour it into the mold, and then clean it up, specially at .177 which is too small to handle. Probably would be faster if you can make it 2 step in forming the entire thing, create your base cast then press the bottom or top part to form the skirt or the top. lead is soft enough anyways.

Hi Duke and Pistolero.

You are both right, casting is time consuming but it also applies to any calibres.

When I cast the large round balls the mold has only 2 cavities, for my .22 molds it is 5 and 10 and the .22 from Noe has 4.

I will have to calculate how much room I have on the blocks and maybe I could get 5 or 6 cavities.

For the time being commercial pellets are still available but I am interested in being self-sufficient.

Anyway I am not ready to give up yet. My shop is operational until late Fall.

R-Gun Pete

That is one reason why you do such good work, going back to the start of your career - probably much earlier.
For your specific case, I know the group size is of secondary importance - you have too many guns to be concerned with pellet testing and pellet matching, so any pellet that will hit and puncture the target is OK for you. But for most others, finding a pellet consistent enough to group well is the prime concern.
I believe you will make a mold that satisfies your needs!

_________________

))))----//----------==
Age quod Agis, et semper ubi sub ubi.

Very nice work, Pete. I have made a few "D" chamber reamers. I used water hardening drill rod. It machines easily with HSS cutters, and it's cheap. I spun the finished reamer in the drill press and heated it cherry then quenched it in water while it was spinning. I read somewhere that method was effective in reducing the warping when quenching. It seemed to work. When hardened, W-1 rod can be harder than HSS, but it has to be kept cool. Slow cuts with lots of coolant save the cutting edge. The reamers I made with W-1 steel cut 4140 barrel steel. Should be good cutting aluminum.

_________________
Theory is when you know how something works, but it doesn't.
Practice is when something works, but you don't know why.
In my shop, Theory and Practice are combined!
Nothing works and I don't know why.

Two lathes and too many projects

Hi Rickplace.

Thanks for the info about the D cutters.

R-Gun Pete

Interesting experiments. As for the head-skirt ratio, there are good designs with quite different ratios. The H&N Field Target Trophy looks quite different than the JSB Exact. The H&N has a big head but I find that it shoots quite well. The JSB has a shallower head and longer skirt and also shoots well in my rifles, providing the head is a tight fit in the bore.

You might already be aware that LEE Engineering now makes a 55gr .22cal bullet mold. Price is $54.59 at Gotenda and $44.98 at Higginson Powders (item #90451). It's quite heavy for airgun experimenting.
https://www.gotenda.com/product/lee-mol ... -rf-90451/

http://www.higginsonpowders.com/images/ ... N_2023.pdf

RCBS and Lyman have been making .224" and .225" bullet moulds for CF rifles for decades.
Looks like Lee is entering that fray as well, with a lot less expensive moulds as per their Aluminum line of moulds
whereas Lyman and RCBS use a mild steel or iron. They are usually referred to as "Iron" blocks.

_________________
Best Wishes
Daryl

Hi TCooper and Daryl. Thanks for your comments.

TCooper your observations on the different proportions of pellets made me compile a whole series of pictures and there is not a specific answer as you mentioned.

Concerning .22 projectiles for airguns, I am not looking for more mold options as I have enough choices as it is. Furthermore the .22 molds for firearms are not the right calibre for airgun and they are also too heavy.

The molds I made produce projectiles over 30 grains and are best shot from PAL rated airguns but in the commercial mold from Noe the solid pellet is just over 25 grains. Depending on the depth of the cavity in the skirt, the other variations are lighter.



For the .177 casting project I want to stay with the regular pellet shape and avoid making slugs. That being said, I am happy with the .22 molds I made.

In the picture below the unfired projectiles are in the middle (it was designed as a firearm bullet with the large part forward but I discovered that in the airguns it preferred to be shot in reverse with the small flat portion as the nose). On the left side they were shot with a Benjamin Maximus and on the left, with a QB Chief into a pellet trap filled with putty. My nickname for the resulting expanded projectile is the muffin.



In this other picture, the slug made from my artisanal mold is nicknamed the Dumbell. Again, the unfired projectiles are in the middle. On the left, the projectiles shot with the Maximus and on the right, with the Chief.



I am in the process of making a new cutter for another .177 test. I will update the post once I have something.

R-Gun Pete

One thing you could try with those, is using a moly bullet coating spray on "your bullets". This will reduce friction & is supposed to increase BC
due to less distortion of the bullet by the rifling(according to Walt Berger). I do not understand the physics of that statement is bases on. This,
of course could be shown by chronographed results.
I do this with the 51gr. bullets I cast for my Condor. At below 1/2 way setting on the hammer spring wheel, it is pushing the moly'd bullets at 906fps.
I need to do some experimenting with them at higher settings, producing higher velocities.
Lyman makes a moly spray for this purpose. Hoppe's moly spray is a lubricant only and wipes off easily. The Lyman moly doesn't wipe off.

_________________
Best Wishes
Daryl

Part 5: After many iterations of cutters and tests, the lead casting mold is started.

Being successful in making two cutters and the associated tryout molds was probably just beginner’s luck because when I tried a third variation I ended up with a mess and a broken cutter.

I guess that I didn’t pay enough attention to what kind of RPM and feed rate I used the first times and consequently got into some trouble. For some reason, since the diameter of the tool was small, I assume that a fast RPM was appropriate.

I experienced a lot of vibration and chatter which should have told me I was on the wrong track. It didn’t take long that a tool failure happened.

With the piece of large diameter drill rod stock I had in my possession, it was taking a long time to machine down to the right size. After finding a local store, I purchased a 1/4” and a 3/8 rods so it would be quicker to make more cutters.

To make a long story short, let’s say that there was a lot of iterations before reaching the end of the road.



With this project I have gained a lot of new knowledges. I normally work with aluminum and brass but this time, to make the cutters, I had to machine steel and also do heat treatment which was a completely different experience for me.

Not knowing what I was doing, it was mostly trials and errors. After another broken cutter, I finally found that my mini-mill had to be set on the lower gears and the knob turned halfway and the feed was fairly slow. I was successful in making a new cutter which survived the machining of five complete cavities (or ten halves/cuts).

At that point, based on my previous tests, I decided that for the final mold blocks I wanted the tail of the pellet at the bottom and the nose at the top to be cut by the sprue plate. My next cutter was machined and a test mold was produced. The result looked promising and, with the same tool, I was ready to cut four more full cavities to start making the working mold.

Before reaching that point the aluminum blocks needed to be prepared. It gave me a chance to make locating holes/ pins and also to work with my fly cutter to make blanks looking like the commercial ones.



In the meanwhile, I had found a solution about how to ensure that both sides of a cavity would be lined up to match perfectly. Since both blocks are pinned and aligned, a quarter inch plate is added in-between which allows enough space to bring down the cutter to the right level and, from there, to start the cut in both directions on the same axis. The tricky thing is to figure how deep to cut in the material taking in account the deflection of the cutter. Having tested the principle with several of the tryout molds, I was confident that I was ready.

After machining the first cavity I am happy with the result. This was done with the new cutter (the one with the tail of the pellet down and the nose up to be cut off by the sprue plate).



This was the first step but the job is not done yet.

R-Gun Pete