I am interested in making a cast of my chamber so I can see what it really looks like, and measure stuff like throat and such. I have only found the stuff brownells sells the Cerrosafe or something like that. Anybody use it, and what do I need to watch out for?

Follow the directions & do not leave it in the chamber too long.

Mr. Humbarger has it right. It's simple stuff to use. I've always warmed the barrel slightly 80 degrees +/- and try to pour down the center of the chamber not letting it slide down the sidewall as you fill the chamber. Then you should get a nice casting. Knock it out after 5 mins or so and you're good to go.

And for all the rest of us, don't forget to plug the bore. I use a cleaning rod with a tight fitting patch.

A few thoughts from my own experiences with it....

1. The tendency the first time is to melt way more than you will need. A tablespoon full is plenty unless you are after a full-length chamber cast. I don't recommend doing a full length cast unless you really need it. Too easy to overfill and end up with some in the locking lug recesses, locking the casting into the chamber. For most "accuracy tuning" purposes, shoulder diameter, neck diameter and length, and throat diameter and length will be plenty of info. All that can be obtained with a tablespoon full or two.

2. If you do end up with a casting locked in a chamber, it is easy to remove....heat the barreled action with a heat gun set on "low" and it will flow right out.

3. It is a lot easier to deal with if you remove the barreled action from the stock before commencing.

4. Be sure to get the casting out as soon as it is solid....which is about 30 seconds after pouring unless one has heated the whole barreled action up above 165 degrees or so.

Otherwise, sure as heck, the phone will ring, someone will come to the door, or some such. Then, if you forget to remove it within an hour of the actual pour, it will expand to the point where you may have to melt it out and start over.

5. Save the formula which comes with the Cerrosafe or other product you are using, so you can calculate true dimensions after the cast is more than an hour old.

With Cerrosafe, if measured exactly one hour after making the cast, dimensions will be right on. If measured before that, dimensions will be slightly smaller than true chamber measurements. If measured after an hour, they will be slightly larger than actual chamber size. But, with the formula, you can calculate "actual" size anytime after an hour.

You'll probably be pleasantly surprised how easy the process is...good luck.

kickass. not that I have had a problem or anything, it is always nice to have something tangible than trying to measure smoked bullets and such for that sort of stuff. Thank you for the input.

Might as well add a little about one way to plug barrels before pouring the casting metal into the chamber.

I use two patches, each just slightly smaller than normal for whatever diameter bore the rifle has. The object is to get the patches to come off of the cleaning rod when they are pushed into place in the bore.


Then I chamber a DUMMY (inert) round. To make sure it is a dummy,I don't have any kind of primer in it, and of course no powder either. I just seat a bullet into a case to normal depth and use that as the dummy round.

Anyway, I chamber the dummy round, then using a cleaning rod with a spear point, or a piece of drill rod at least 1/8th inch smaller in diameter than the bore, I shove one patch down the barrel from the muzzle until it contacts the point of the bullet in the dummy round.

Then I withdraw the rod, leaving the patch up against the bullet. Next I run in a second patch and leave it up against the first patch, the same way.

After withdrawing the rod, I open the action and take out both the bolt and the dummy round.

Now I'm ready to make my pour.

When the pour is done and the casting material has solidified, just run the rod back down the bore and give a little tap on the patches & casting. Should pop right out of the breech, with little or no effort. (If you re using a cleaning rod, remove the spear point before trying to shove the casting out. No sense risking having the tapered point shove the tip of the rod sideways into scraping contact with the lands.)

Easier and quicker to do all this than to type it. [Grin]

my mentor used an old metal funnel, that he got darn hot (actually, he just put the cerro in it and hit it with a propane torch .. i use a hot ait gun) .. to get in the chamber

jeffe