How to make a Lead chamber cast

Beginners guide on how to make a .303 lead chamber cast

I hope that this is of some use or help to anyone who is wondering how to make their own lead chamber cast for their .303.

This is an alternative option than that of my previous “how to” with sulphur guide, I like this method as it’s a lot more accurate.

Items you will need

Electricians tape, this is to help create a barrier between the metal rod and your precious rifling

A hammer.

Steel rod, with a diameter of say .300

A fired case, sized, WITH fired primer still in place.

Lead, I normally have a plastic container with reject lead projectiles that for one reason or another were not up to standard, say gas check poorly seated, an imperfection not weeded out earlier etc. These I keep for recycling or projects like this.



SOFT lead, the softer the better, I use lead that is used in lead light windows.


The .303 mold that produces the longest and fattest projectile and a ladle.

A gas torch

As in the previous “how to” make sure you are wearing appropriate clothing, safety eyewear, gloves etc. Also you can have a set of pliers hold the case as not to task load. Also again like before, have an uncluttered workbench with NO other rounds anywhere near you. Do not have any rounds that could be mistakenly picked up and used in any aspect of this. So again clear the bench!

Remove the decaping pin from your sizing die and size a case, but just make sure that the primer is not removed; ALSO please make sure that it is a fired case and not one you have ready for reloading!

Now fill the case with the reject lead projectiles ensuring that they don’t have the gas check still attached, once you have that case full, heat the case and melt the lead, top up and redo the process until the lead is up to the case neck.


Now remember that case is going to be hot! Get a flat head screw driver that is smaller than the case neck and gently remove smooth out any high points. We want the top to be as reasonably flat as possible. Place to one side.


With the very softest lead you have make a lead cast projectile, a long projectile is best.  Dont size the projectile. When fully cooled seat the round into the neck of the case. The lead in the body of the case will ensure that the projectile can not be forced back into the case.

Get the metal rod and check the diameter of the rod, check in a few places. (You really dont want to force a rod that has a bigger diameter than your bore of your rifle, into your rifle…..this is bad!) Then place a couple of wraps of the electrical tape at various intervals along the rod, not too much so that it jams and can’t be feed into the barrel. This way you have a rod that will snugly fit in the barrel without any metal touching the barrel (this is good!).

Carefuly chamber the lead filled case and close the bolt.

Inset the rod into the barrel till you feel it meet the head of the projectile. Place the butt of the rifle on a piece of hardwood, not the concrete floor and not anything to soft as to absorb the impact. 

Strike the metal rod firmly but gently, (not like an 800 pound gorilla), as you want the energy to transfer along the rod, NOT bend the rod! Now here is what is happening, you are compressing the soft lead into the lands and groves. As it’s a long projectile it will mold into all the areas you wish to measure.  After a few strikes the rod will “bounce” back as it’s pushed the lead as far as it can go and is springing back.

Open the bolt and gently tap the round out.

The end result should show the actual dimension of the chamber. It will show any erosion and or any other issues. It also allows the most accurate way of measuring the lands and groves. Now the reason I prefer this against sulphur as the lead stays static, it doesn’t shrink. There is another similar method but it requires removing the woods and applying heat and a lot of it to the chamber, not fussed on that method.

If you don’t see any imprint or rifling either you were too gentle in striking the rod or there is none? What you could do, and I must stress I’ve not done this, but make a second SOFT lead projectile, place this in the chamber if you can use the round you have just made to push it into the rifling and close the bolt on the lead cast round and extra projectile. With the rod again go through the same process.  Either you will see rifling or the throat erosion is rather big!

I hope that this helps, if you have any questions or comments please feel free to make them, it the only way to improve or learn!