View Full Version : Bullet mold

jim 44-40
02-20-2022, 02:59 PM
Is it possible for one to make a bullet mold pattern with enough draft on it so I could use it to sand cast a mold from brass?
Without enough draft it would not pull out of the sand without messing up the cavity.Would not need handles on it.

Winger Ed.
02-20-2022, 03:28 PM
"One" probably could, but I sure couldn't.:bigsmyl2:

I'd think even with a lost wax type process, the inside finish of the new mold block
(even if you had close enough tolerances) wouldn't be smooth enough,
and would still have to be 'dressed' or polished somehow like cast engine parts are done.

For the inside part of a mold---- that gets you back to a spinning cherry sort of deal.

04-07-2022, 09:52 AM
I would think you absolutely could. I would be curious about making one square with minimal infill. Packing it into the sand cast then melting the plastic out. You could make some extra space on the bottom for the plastic to melt into if you didn't want to tip the sand mold. Very interesting idea!

04-07-2022, 11:32 AM
Sand castings have a very rough surface finish. Most are machined afterwards and that would NOT be a good use of your time.

I have done a lot of sand casting in brass and other metals and the surfaces were in definite need of machining to be anything close to acceptable.

Go ahead and try it. It' your time and material. I would just buy a mold if I needed anymore! Have tons now.

And a 3D printer DOES have its limitations. I have two.


04-07-2022, 01:05 PM
With the advent of powder coated bullets the lube grooves aren't needed. This eliminates the complication of split molds and special cherries. I've made molds for my .577 Snider by plunge milling an aluminum block with a 1/2" ball-end mill and then boring out to .577 diameter. To aid extraction from the mold a 1/8" hole in the nose end plugged with an aluminum rod allows sticky bullets to be tapped out.
A piece of drill rod can be turned with whatever nose profile is desired and used to mill aluminum blocks. If hollow points are desired the nose plug can be made with a tapered end. Super precision isn't needed since bullets are sized after powder coating. I'm surprised that Lee Precision isn't making grooveless molds since they are so much easier to fabricate.

04-07-2022, 01:57 PM
It seems like an awful lot of work and as said above, you would need to machine after anyway.

So, yes you could but why? If you have a furnace and some scrap brass then sure I guess you could cast a lump of brass but you would have to machine it afterwards. The cavity would have to be machined and the top surface under the sprue plate.

Much easier to buy some round bar and make a "cylindrical mould". I came up with this idea about 50 years ago and figured I was pretty smart... except Barlow at Ideal beat me by about 75 years!

https://i.postimg.cc/YC0cdjKd/Ideal-Cylindrical-Mould-Diagram.jpg (https://postimages.org/)

Looks like a cast body on this one but I make mine out of 1 1/2" round bar and use a more traditional sprue plate. So far I have made moulds like this for .308, .303 British, PP .30 cal., PP .44 cal. full bore .30 and .303 cal., full bore .44 cal., 20 ga. slug and many 12 ga. slug.

They can be made as shown with a nose form/ejector or HP or FP with an ejector pin. They can also be made in nose pour and HB which is how most of my shotgun slug moulds are made.

I have made smaller (.30 cal.) moulds using D reamers and larger moulds using a boring bar and/or D reamer for nose profile.

They are easy to make and bullets/slugs are perfectly round with no seam. They can be bored to near size then lapped to final size or if D reamer is used they should be good to go after reaming.

Bullets can be smooth or knurled. If smooth I usually use a nose bore rider design and tumble lube. If knurled I make the cavity about 0.003" undersize then knurl to final size and tumble lube. One of my best shooting .303 British boolits is a copy (more or less) of the 314299 Lyman but casts at 0.315" and weighs 215 grs. Tumble lubed it shoots very well. You can't easily put a gas check shank on but PB gas checks could be used. I use filler which works for me.


10-27-2022, 07:09 PM
The short answer is YES.

If you own a resin 3d printer there are specific resins made just for this purpose. Lots of jewelers use this type of resin and I think that lots of dental laboratories use this type of resin too.


10-27-2022, 07:24 PM
Lost wax method? Make any design and size bullet ? See how it works ?

10-27-2022, 07:56 PM
if I am reading you right, you want "draft" so the bullet will release,--why? the bullet would be tapered by several thousands. maybe useful

10-29-2022, 12:11 AM
I've actually 3D printed 9mm and 45 cailber bullet molds themselves using the high-heat-resistant resins that are available. It was a while back now that I posted that project here on the CastBoolits site. I also included videos of me casting with these molds.

I quit posting anything more on this subject cause both my Facebook and YouTube accounts were targeted by their algorithms and either deleted my videos outright or they threatened to ban me from their platforms. The resin manufacture that was sending me free resin to run my project was also spooked into capitulating and quit offering the free resin.

I felt that if I couldn't post my proof that it worked, it was pointless to keep posting any more of the advances I had made with that particular project. All of this to say, I found that I didn't really need to use the Lost-Wax method in order to make myself some bullet molds out of metal. I just printed the molds on my 3D resin printer and used those to cast my bullets.


11-06-2022, 09:19 AM
What resin was able to stand up to 600+ degree lead?

11-06-2022, 08:06 PM
What resin was able to stand up to 600+ degree lead?

Siraya Tech Ultra White 3D print resin.

If I remember correctly, it was actually slightly higher than the melting point of lead. At first my 3D printed molds would only last for about three or four bullet-casts before they were ruined by the heat.

With multiple tweaks to my mold's interior configuration and workflow, I was able to go from only casting three or four bullets to over twenty good usable cast bullets before the molds started showing signs of no longer being able to withstand any further heat torture. From there I kept tweaking until I was confident I could cast enough bullets out of an individual 3D printed mold that it would make it economically feasible to just print my own molds.

Of course, metal molds are far superior. My 3D printed molds were just a proof of concept project.

At the time, I did an ongoing writeup on this project at the following link here on the CastBoolits forum.


I started out casting pellets for my pellet guns and from there I sort of expanded to 3D printing bullet molds.