Chamber casting
- Thread starter Royzo
- Start date
- Location
- Western Manitoba
You probably want a product called "Cerrosafe" - I've got it from Brownell's. Melts below boiling point of water, shrinks upon solidifying, then an hour later it has swelled to exact size. An alternative that I have not tried for chambers is to "lead pack" - pure lead pellets, gently tamped into chamber with bolt closed - the lead pack works great for getting a reading on chamber throat, but starting with a fired cartridge case that is filled half way up the neck with lead. I can't see why that wouldn't work for an entire chamber?
The Cerrosafe isn't cheap but it's reusable pretty much indefinitely.
Another option would be one of the harder industrial waxes as used for the lost wax method such as custom jewelry and forming of other small intricate parts. You'd need to look into how much it shrinks or if there's grades of this wax that will resist shrinking as it solidifies. But the harder waxes would do just fine for handling and measuring if they hold the size correctly.
If you're after more of a rough idea than and exact shaping even candle wax will work. Or perhaps thoroughly but smoothly grease the chamber then fill it with an epoxy then use a cleaning rod to bump it out after it cures.
If you go with the Cerrosafe option you'll want to warm up the receiver and chamber area of the barrel with a propane torch. You'll want to get it to where it is still well below the boiling point so water won't "sizzle" when touched to the metal but it's still way too hot to hold with bare hands. Pouring the Cerrosafe into a cold chamber is a great way to get a very incomplete formation.
Regardless of the method you'll need to put a little wad of paper towel down into the bore so it's just a little ahead of the leade of the chamber throat. This was should be a pretty tight rammed fit so it can't shift at all.
Another option would be one of the harder industrial waxes as used for the lost wax method such as custom jewelry and forming of other small intricate parts. You'd need to look into how much it shrinks or if there's grades of this wax that will resist shrinking as it solidifies. But the harder waxes would do just fine for handling and measuring if they hold the size correctly.
If you're after more of a rough idea than and exact shaping even candle wax will work. Or perhaps thoroughly but smoothly grease the chamber then fill it with an epoxy then use a cleaning rod to bump it out after it cures.
If you go with the Cerrosafe option you'll want to warm up the receiver and chamber area of the barrel with a propane torch. You'll want to get it to where it is still well below the boiling point so water won't "sizzle" when touched to the metal but it's still way too hot to hold with bare hands. Pouring the Cerrosafe into a cold chamber is a great way to get a very incomplete formation.
Regardless of the method you'll need to put a little wad of paper towel down into the bore so it's just a little ahead of the leade of the chamber throat. This was should be a pretty tight rammed fit so it can't shift at all.
I put the receiver in a vise, barrel down, and use modeling clay to make a funnel around the chamber, to prevent the cerrosafe from sticking to anything that could allow it to grab on. like an extractor cut out for example.
I use a hair dryer to heat the chamber, and a torch to melt the cerrosafe in a bullet casting ladle, and to pour it in the chamber.
I use a hair dryer to heat the chamber, and a torch to melt the cerrosafe in a bullet casting ladle, and to pour it in the chamber.
I have some cerrosafe that I have been using for years. As others have said, put a small piece of patching material in the bore so that it does not run down the inside of the barrel. My interest is in antique guns and some have rough chambers. If you suspect a rough or bulged chamber, instead of using cerrosafe, use paraffin wax and tie a piece of cotton string to the barrel wad or plug before pouring. The purpose that if the wax cracks or breaks when you push it out, the pieces are all held together by the string. The reason for paraffin in the rough chamber is that it is infinitely easier to knock out than cerrosafe
cheers mooncoon
cheers mooncoon
fingers284
CGN Ultra frequent flyer
- Location
- Alberta Cowboy Ranges
I have used sulfur but it's not pleasant sh#%t to use... the fumes when melting are not something you want to breath in so do it outside with a breeze blowing downwind. Sulfur will give you a rudimentary look at what your chamber is shaped like and that sometimes is all you need to identify the round you need but it is too fragile to use for precise measurements like you get with Cerosafe.
I had a friend that worked as a tool mark and firearms tech in the State firearms lab. He had used sulpher at times for making impressions of different things including prints and tracks in snow.
nope
the issue with chamber casts is they need to release to be measured and they need to be an exact copy of the chamber.
cerrosafe first contracts allowing for the mold to be extracted and then, within an hour, it expands back to what the real chamber size is.
I'm sure sulfur doesn't do this.
