The Science of Swaging: Why It Beats Casting and Punching



The Science of Swaging: Why It Beats Casting and Punching​


When it comes to precision projectiles, not all methods of making them are created equal. Many shooters are familiar with casting (melting and pouring lead into molds) or punching (stamping out shapes with presses). But the process of swaging — forming projectiles under controlled pressure — is what separates good enough from world-class accuracy.




Casting vs. Punching vs. Swaging


  • Casting: Simple, but prone to weight variations, voids, and surface imperfections. Heat and cooling cycles can cause inconsistencies.
  • Punching: Faster for mass production but sacrifices precision. It’s efficient, but dimensional tolerances are looser.
  • Swaging: Uses pressure and precision dies to form each slug identically, with tight tolerances, perfect concentricity, and smooth finishes. Every dimension can be controlled down to the thousandth of an inch.



Why Swaging Matters for Airguns


Airguns are uniquely sensitive to inconsistencies. A small difference in diameter, weight, or concentricity can throw shots wide — especially at long range. Swaging ensures:


  • Uniform weight distribution → tighter groups
  • Smooth surfaces → less barrel fouling, better BCs
  • Consistent diameters → reliable chambering and seal

That’s why when you’re stretching shots out past 100 yards, swaged slugs outperform almost every other method.




Corbin’s Role in the Industry


For over 50 years, Corbin has specialized in swaging equipment — building the dies and presses that supply some of the most respected slug manufacturers in the world. Many of the PCP brands airgunners trust today made Corbin their first call when they decided to get serious about precision.


From hand tools to fully automated hydraulic systems, Corbin has set the standard for uniformity and repeatability in ammunition tooling. Entire companies have built their success on Corbin equipment.




Why This Matters to You


The next time you send a slug downrange and watch it land dead-center, it’s worth remembering:


  • Precision isn’t an accident.
  • It comes from the right process, the right design, and the right tooling.
  • Often, that story begins with swaging — and with Corbin.
 
What would be the entry level cost to get into swaging? Interests would be in .22 only. Weight in the mid 20gr.
Depending on what you want ..... but you are going to need the S-press, and a set of dies and the material to make the slugs. If you are able to grab a set up when there is a sale it isn't to bad. It really depends on how much you shoot, and how much you are willing to spend. But if you are shooting a lot of slugs then the press is a viable option. A complete set up will cost about as much as a medium to high end airgun.

Then with the press you are going to need a GOOD scale. I was using a digital RCBS scale, but I was able to find a three beam scale that is great. I am able to get much more accurate weights with the beam scale, and will strictly use that when weighing the slugs.
 
And then there is your time ? or a long cold winter side of the hobby ?

there involves a set up time and clean up time most people do not have room to have a separate shack to do this in .
Yes, swaging does take an initial investment and time. I’ll be the first to admit that it’s not for everyone. However, you can still buy swaged bulk slugs and experience the difference.
 
And then there is your time ? or a long cold winter side of the hobby ?

there involves a set up time and clean up time most people do not have room to have a separate shack to do this in .
@beerthief Why would you think that you'd need a separate shack? It really only takes a workbench/table's worth of space. I can't speak for anyone else, but I like doing some things for myself among other things. I don't mind spending time to swage when I feel like it. I takes me a while to shoot through a batch of slugs.
 
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CnC turned slugs are quite consistent. The downside is the antimony and tin added make the slugs extremely hard . This can promote fouling and decrease life of the barrel substantially.
Altaros slugs are CNC turned. Also……..
  • Almost pure lead (99.9% Pb) for maximum expansion at the target and friendly to the barrel
  • Slugs made with this technology currently hold a world record of hitting target on 1 MILE from an airgun!
 
And then there is your time ? or a long cold winter side of the hobby ?

there involves a set up time and clean up time most people do not have room to have a separate shack to do this in .
It really doesn't take long to punch out a bunch of slugs. Just put on some music or a pod cast and start making. It really is the same as reloading for your powder guns.
 
The funny part of this comparison.....
If you do your casting Correctly...
Final step is to Swag them.... Sort of..
You need to run them through a sizing die..(possibly lube them too)
So you are Swaging them to size.......also helping remove surface imperfections......
why not skip all the casting part and just swage then
 
@beerthief Why would you think that you'd need a separate shack? It really only takes a workbench/table's worth of space. I can't speak for anyone else, but I like doing some things for myself among other things. I don't mind spending time to swage when I feel like it. I takes me a while to shoot through a batch of slugs.
I really was just pointing out time and space required as some people might not think in those terms . Personally i would have to set up a space and take the required items out and set up to swage or punch. then i would need to take down and store the Equipment and supplies and then clean the bench.
This is all fine If you can do it and i like reading about it . Swaging .177 wadcutter pellets might interest me ? although pellets are usually pressed ?
Edit : I think the separate shack came from a post i just saw , but he was pouring lead I now remember .
 
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I really was just pointing out time and space required as some people might not think in those terms . Personally i would have to set up a space and take the required items out and set up to swage or punch. then i would need to take down and store the Equipment and supplies and then clean the bench.
This is all fine If you can do it and i like reading about it . Swaging .177 wadcutter pellets might interest me ? although pellets are usually pressed ?
@beerthief It doesn't require a lot of space if you have room to make for a workspace. Swaging small caliber projectiles is a PITA for me. I don't think we can swage pellets. If there's a way I haven't seen it.
 
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why not skip all the casting part and just swage then
Actually .... I Do......
swage61.jpg


The only Casting I am starting to do...Cast raw cores to be Swage..... from rejects, trailings, re-do's

core%20moulding.jpg
 
What would be the entry level cost to get into swaging? Interests would be in .22 only. Weight in the mid 20gr.
@Avator Probably around $1800. That should get a basic setup shipped to you with what's needed to start swaging aside from a table to mount the press to.

 
The new Corbins look good, almost as good as Altaros but I give the edge to the CZ made slugs. I’m all about USA made and with added shipping charges the Corbins look even better. Good product. Please make some boat tails in .25 also.
We just finished the .250. What grain weights would you like to see?