Gunsmithing Chamber casting Updated with pics

[TN-MadDog]

Hey guys, I could use some help learning how to cast a chamber. I want to make a chamber cast of a AR upper chambered in 300 Whisper. I have read all that I could find about the process but I still have some questions.

The main issue that I am concerned about is figuring a way to to get "just the right amount" of the melted Cerrosafe into the chamber. The 300 Whisper is a pretty small cartridge and I am afraid of getting too much in there and over flowing the chamber. Then it would be very difficult to get out. If I don't get enough then it would not be a good chamber cast.

So, I guess that you could use a long neck funnel to pour it in. But how would you know when there was enough? With the funnel in place, I would not be able to see how much is in there. If I pour a little and look, will it set up before I can get more in there?

I am sure that it would be easier if I pulled the barrel but I don't have the tools needed to do that.

sorry for the long post. I would appreciate any advice.

Thanks,

Joe

 

[Victor N TN]

Re: Cerrosafe chamber casting

I clean the chamber & barrel really good to remove all the fouling I can. Follow that with a couple of patches w/ light oil. Wad a couple of patches and use a cleaning rod to act as a "stopper" in the barrel. I usually take the barrel off the action on my competition rifles. To use the casting material in an assembled action use a "Tablespoon" measurement spoon to limit the amount of material you use.

I normally only cast the throat, case mouth, neck, shoulder junction areas. You want to keep the casting small. The more material you use, the harder it will be to get it out. If you have an older barrel that has a rusted & pitted chamber... DO NOT CAST a rough chamber. The melted material gets in the rust spots and you have to use a steel rod and a hammer to BEAT the casting out. Don't ask how I know this.

Good luck.

 

[TN-MadDog]

Re: Cerrosafe chamber casting

Victor, thanks for the information and advice.

How quickly does the Cerrosafe set up? If I use some sort of funnel to direct it to the chamber will it start to set up as it is draining down or do you have some time to work with it?

Thanks,

Joe

 

[Victor N TN]

Re: Cerrosafe chamber casting

I have done it probably in every month of the year. When the metal is very cold like left in a truck after a snow storm, bring it in and un case it for a day or 2 to give it time to warm. When you start with the Cerrosafe you have SECONDS to get it in place. It handles a lot like lead. If you have ever done any bullet casting. I have a tin can that I cut to shape with tin snips that I place on a stove eye to melt. An aluminum measuring spoon for 1 tablespoon usually does me pretty close. Remember the more metal you pour in the harder it will be to extract. Even using a light coat of oil in the chamber. Be sure to plug the barrel so the metal doesn't run down the barrel.

Good luck.

 

[TN-MadDog]

Re: Cerrosafe chamber casting

Thanks for the reply. I ordered some Cerrosafe today and will give it a try. I will post back with pics when I get it done.

Joe

 

[Victor N TN]

Re: Cerrosafe chamber casting

All the material I have came with instructions saying to wait 1/2 hour after casting to measure the dimensions you want. After several hours it cools and contracts to the point that you can't measure it again.

Remember to oil the chamber before you start.

Good luck.

 

[TN-MadDog]

Re: Chamber casting Updated with pics

Well I got it done without too much trouble. I did do what I was afraid of and overfilled the chamber. Had to use my torch to gently heat that part util I could get the cast out.

Here are a couple pictures. Does anyone know if that looks like the correct amount of freebore for a 300 Whisper? Using a Hornady OAL gauge is giving me lengths way too long to load near the lands.

Joe