Chamber cast???

[Ickisrulz]

I got some chamber casting material from Rotometals. I need to cast a chamber of a Win 70. I plan on melting the material using a clean ladle and a propane torch.

How do I get the stuff into the chamber without making a mess?

[NHlever]

On an assembled gun it is often necessary to make a tube, and funnel arrangement. Since the metal melts at around boiling temperature for water, the tube material doesn't have to be anything heavy, or special. Here are some basic instructions from Brownell's.
http://www.brownells.com/.aspx/pid=384/Product/CERROSAFE_reg__CHAMBER_CASTING_ALLOY

[SmuvBoGa]

I have been able to use a hot air gun to melt the stuff. Get it out quick after it sets up - wait too long & you WILL be cussing it out. Try a wooden dowel with a wad of cleaning patches on top of it - melt the casting stuff in a dog/cat food can (make a pour spout on the can before you do the melt) & pour it down.

[BABore]

First off remove the stock. Although the melting point is not very high, it's high enough for a stock finish and accidents do happen. I took a 4-5 inch piece of 1/4 dia. copper tube and put a double bend in it or dogleg. I used a flaring tool to open one end up so it was easier to pour into with the ladle. Clean the chamber & bbl well, then push in a patch and tight fitting jag from the muzzle so you leave about an inch or so of the rifling exposed. Unscrew the jag from the rod. Warm the bbl and action and also the copper tube. Pour quickly and precisely. Trickling it in slow will result in wrinkles just like in your boolit molds.

[geargnasher]

Or..........Do what I learned from some members of this forum: Skip the BS and make and impact slug. The slug will be more accurate and withstands the wear of measuring tools much better than Cerrosafe. No need to dismantle the gun or burn yourself/gun finish/surrounding work area.

Gear

[MtGun44]

Temps are low, use a file folder and tape to make a nice funnel. Melt in a
non-waxed cup and handle with gloves. Pour into the chamber. Don't over
think this. File folder card stock if plenty strong enough and heat is LOW, warm
with a hair dryer or heat gun on LOW to melt.

Bill

[Crash_Corrigan]

I recently did a chamber cast with cerro safe on an old 8 MM Mauser. This was an old commercial action and my reloaded rounds would not chamber.

I very carefully cleaner the chamber and barrel. Oiled both well and ran a clean patch to remove most of the oil .. I plugged the barrel two inches below the chamber with a patch. I made a funnel of a magazine cover rolled into a funnel and melted the cerrosafe in a tuna can with propane torch.

I carfully inserted the small end of the paper funnel into the chamber and quickly poured the melte cerro safe into the chamber without overfilling it.

I removed the funnel and waited a minute and then punched out the slug with a cleaning rod from the muzzle end.

Turned out that my barrel started at the end of the cartridge mouth.. No freebore at all. Lands and grooves immediately after the case mouth and the diameter there was .3235 and rapidly down to .323.

Now I will have the chamber reamed to give me .3255 at the case mouth and slowly bring it down to .323 about 3/4 " down the barrel. This will allow me to chamber my reloads safely and still get good accuracy.

Although this gun was made in the 20's the barrel looks almost new. Very sharp corners on the lands and grooves and bright and shiney with no pitting.

I have no idea what ammo was being used in this gun as standard military and commercial ammo does not chamber in this gun at all. To use it as it is I would have to reseat my boolits down into the case much deeper and I do not want to do that for a buncha reasons. Including the rounds will look kinda funny with only the round nose of the boolit sticking out. Maybe I am too fussy.

[Doby45]

Maybe it looks all nice and new and shiney cause as you said they couldn't use it and it just sat in an armory somewhere, waiting for Crash to show it some love. I am surprised you didn't melt the cerro safe in your hand, being as they are asbestos and all. ;)

[BABore]

Or..........Do what I learned from some members of this forum: Skip the BS and make and impact slug. The slug will be more accurate and withstands the wear of measuring tools much better than Cerrosafe. No need to dismantle the gun or burn yourself/gun finish/surrounding work area.

Gear

+1

I have done several good chamber casts with Cerrosafe alloy so I could design boolits for an exact fit. The casts were done "by-the-book" and turned out very well. They were measured to the nearest 0.0001" at the specified period of time. In all cases the resulting boolits were "dead nutz" on the money for size. Also in all cases they turned out small and had to be seated out much farther than anticipated. I no longer trust them for precise measurements. They're fine for a decent look at the throat shape and length, but's that's as far as I'll go.

You can do a search here for doing a proper impact slug, so I won't go into it. One common problem I've seen is that you would normally fill a fired case with hard lead to about 0.125" below the case neck to use as a foundation. Another method is to put a steel, aluminum, or brass rod inside of the case. The rod method works ok if you machine it to a precision fit. Otherwise the expanding lead slug can deform and shorten the case by collapsing the shoulder some. Pouring hard lead can result in the same thing cause it anneals the entire case dead soft. A much better use for that Cerrosafe is to use it to fill the case. It's hard and has a low melting point.

To get a useful impact slug, you have to have a reference point to work from. The foundation case needs to be checked for length and recorded. Any shortening due to collapse needs to be measured and noted. The designer can then use these case length dimensions as a reference to set the boolit position properly.

[nanuk]

BABore just gave me an idea for the "CerroBend" I have.

[Ickisrulz]

+1

I have done several good chamber casts with Cerrosafe alloy so I could design boolits for an exact fit. The casts were done "by-the-book" and turned out very well. They were measured to the nearest 0.0001" at the specified period of time. In all cases the resulting boolits were "dead nutz" on the money for size. Also in all cases they turned out small and had to be seated out much farther than anticipated. I no longer trust them for precise measurements. They're fine for a decent look at the throat shape and length, but's that's as far as I'll go.

You can do a search here for doing a proper impact slug, so I won't go into it. One common problem I've seen is that you would normally fill a fired case with hard lead to about 0.125" below the case neck to use as a foundation. Another method is to put a steel, aluminum, or brass rod inside of the case. The rod method works ok if you machine it to a precision fit. Otherwise the expanding lead slug can deform and shorten the case by collapsing the shoulder some. Pouring hard lead can result in the same thing cause it anneals the entire case dead soft. A much better use for that Cerrosafe is to use it to fill the case. It's hard and has a low melting point.

To get a useful impact slug, you have to have a reference point to work from. The foundation case needs to be checked for length and recorded. Any shortening due to collapse needs to be measured and noted. The designer can then use these case length dimensions as a reference to set the boolit position properly.

I appreciate the response. I just don't understand it. If the casting was good...why the problems?

[geargnasher]

Cerrosafe and similar low-temp alloys are very soft and shrink as they cool and age, so there is a narrow window, IIRC 30 minutes or so after casting, in which they represent accurate dimensions of the chamber. Like BABore said, you can do everything right but don't bet the farm that your meaurements will be good enough by which to design a boolit. An impact slug, if done properly, will be accurate today and ten years from now, so you can go back and remeasure it or check a part of it that you didn't think to record the first time.

Gear

[dromia]

Texasmac's article on this subject is very good.

Its here: http://www.texas-mac.com/Determining_Case_Lengths_Chamber_Casts_and_Impact_ Impression.html