Using CerroSafe

Melnic · Feb 18, 2021

With the recent posts (and many older posts) about cerrosafe I thought we would be good to have a running thread here on MDShooters dedicated to and helping others doing chamber casting. Yes, there are threads on other boards, but always good to have one here.

My first venture starts with being gifted some Cerrosafe. I wanted to get a chamber cast of my .41 swiss M78 Vetterli which is a black powder rimfire to centerfire conversion. Read instructions from Brownells and then a few interwebs post. One stuck with me where the guy said he needed to pop it out quicker. Well, the guy was wrong and I was wrong to listen to this guy. Here is the instructions from Brownells

https://www.brownells.com/userdocs/learn/Inst-446.pdf

Well first 2 attempts I think I tried to pop them out too soon cause they were stuck and I heated up the chamber w/ a torch to pop them out onto a cardboard sheet which is a bit of a mess to clean up after some went into the trigger area. Live and learn. Second time It was so soft that the rod drove INTO the not yet hard mix and that was a mess to clean up. Definitly needed to let it set up more.

Per advice from the Gifter, I switched to a pistol barrel and used a spare glock clone. Warmed the area I was casting with a heat gun for about 15 seconds (I did with the vetterli but I may have warmed it TOO MUCH). I also skimmed the heated mix with a q tip. This time I poured too much and it spilled out the breech onto the bench.

Popped it out in exactly 30 minutes (piece of cake, came out with finger presser on the rod) then took some measurements at exactly 30 minutes later (60 minutes after initial set up after pour).
There are some imperfections further up in the chamber but the case mouth and at the rifling look good.

I took a cheap $3 ladle from Giant and bent it to allow it to pour better.

Wondering to get a better cast, did I not heat up the barrel enough or did not heat up the cerrosafe enough?

GunBum · Feb 18, 2021

My best advice when casting chambers and throats with Cerrosafe....

Perfect is the enemy of good enough.
Could the chamber cast be better? Yes.
Does it need to be better? Probably not, but only you can see the actual casting.

John from MD · Feb 18, 2021

GunBum said:
My best advice when casting chambers and throats with Cerrosafe....

Perfect is the enemy of good enough.
Could the chamber cast be better? Yes.
Does it need to be better? Probably not, but only you can see the actual casting.

This is good advice.

If you are looking to get an actual bore measurement, then a close to perfect cast is necessary. In this case, heat the barrel up more. Heating the Cerrosafe too much creates dross and makes for grainier casts.

If you want to see how much lead is in a given barrel, you don't need to be as critical as you are just looking at the space between the chamber and rifling.

If you have an overbore rifle, like a 22-250, 220 Swift, .243 or 25-06 Cerrosafe is good for checking the throat wear as you use the rifle. I used to supply a cast to people I built varmint rifles for so they could check them from time to time as distance accuracy was important for them.

Melnic · Feb 18, 2021

Ok
2nd one
Popped out Easy at 30 minute mark

What went wrong?

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GunBum · Feb 18, 2021

Looks like the cerrosafe is too hot.

John from MD · Feb 18, 2021

Cerrosafe too hot I'm betting. I melt mine in the same type of ladle as you do but I use a Harbor Fright heat gun (with the multiple temp leds) instead of a torch.

Melnic · Feb 18, 2021

One thing I did different was to use w tip and run CLP around the. Other end to clean up
First time I used Rem oil sprayed onto a q tip

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Doco Overboard · Feb 18, 2021

I pour mine from a soup can with a little snout crimped into the top.
I think the can helps to keep material temp up until you can get the pour made.
I’ll also heat barrel up with low temp heat gun until is good and warm.
I think if you can pop the cast free at the point of its maximum contraction And not lose too much heat by not having the ladle/ can too far from the barrel you can get a good one made.
Cerro-Safe is a whole lot easier to use than powdered sulfur for sure no doubt about that.

John from MD · Feb 18, 2021

Practice makes perfect, err close to perfect anyway.

Melnic · Feb 18, 2021

Took my 60 min measurements.
grainy/crystalized one measurements are the same as the first one, but really gotta make sure your not tight on the calipers or it crushes into the crinkle.

Just to add to the thread, what should I be measuring?
I'm measuring:
Diam of the case at the mouth edge.385"
Diam of the chamber past the mouth at the mouth .361"
Distance to rifling .160"
Distance from mouth to the point where the chamber is reduced to the diameter of the bullet I load (.356") = .160" (at the point of rifling begins)

John from MD · Feb 18, 2021

It tells me that you have a chamber that is in spec and that it has enough lead so that you shouldn't have any problem shooting Lee 125 RN or 120 TC bullets.

Archeryrob · Feb 18, 2021

I've reconsidered and will do the slugging with a soft lead round over a pre-shot case full of hard lead. Somewhere in reading that they talked about Cerro varying in diameter slightly where cold formed lead would not. Maybe I'll try it both ways eventually. I think I like the idea of the cold slugging now better. I can line up slugged case next to seated round and measure both for seating depth and diameter at the length.

I can't load anything anyways. I can't find my mold, or primers and the wife just found IMR 3031 for the 30-30 today.

Melnic · Feb 18, 2021

Archeryrob, I mold lead for bullets ALL THE TIME. I can say this, after doing the cerrosafe on that glock aftermarket barrel, I'm warming up to it over lead. Especially since its a lower temp and I can get it out of the gun if stuck so much easier. Plus I can do all this in the gun room.

I'm going to go back to the one I failed on the first time and try again tonight after doing the glock barrel a 3rd time

Archeryrob · Feb 18, 2021

Did you buy a pound or half pound of that stuff? How far does it go?

I'm going to try the lead and just go slow.

Doco Overboard · Feb 18, 2021

How are guys measuring depth of the grooves?

John from MD · Feb 18, 2021

Doco Overboard said:
How are guys measuring depth of the grooves?

You can't really do it with a caliper.

This is what you need if you are in the business. https://www.grainger.com/category/m...h-gauges/digital-depth-gauges?categoryIndex=2

This will work for a hobbyist. https://www.grainger.com/category/m...epth-gauges/dial-depth-gauges?categoryIndex=1

Melnic · Feb 18, 2021

Finally able to measure the .41 Swiss
I still had to tap out hard with brass rods and I know why now
The throat is really eroded and pitted.
I learned from this cast that I can get away with a much longer neck on the case which will allow me to run my bullet out longer.
why would I want to do that you ask? Well the way the tube feed system is on the Vetterli M78, the cartridge OAL must be a certain length within like 0.020" or it won't feed properly and you have to single load. The other thing is that with all the erosion, I can run the bullet much closer to where the rifling starts which with the erosion is way out there even beyond where my cast started. I am definitely NOT looking to eek out much accuracy out of this the way the erosion is. I will be using a load known good by other and much below the max based on Quickload that I just got in.

I want to see if I can use my borescope and try to measure where the Lands start on the rifling next.

with all the test casts and finally the .41 swiss, I think I"m comfortable doing other guns now. I'm liking using the heat gun. More controlled than the torch

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Doco Overboard · Feb 18, 2021

John from MD said:
You can't really do it with a caliper.

This is what you need if you are in the business. https://www.grainger.com/category/m...h-gauges/digital-depth-gauges?categoryIndex=2

This will work for a hobbyist. https://www.grainger.com/category/m...epth-gauges/dial-depth-gauges?categoryIndex=1

I thought that's what you were measuring when you measure the OD of a slug driven through a rifle bore with an even number of grooves. The groove diameter.
Good calipers or a micrometer will suffice for that.

Melnic said:
Finally able to measure the .41 Swiss
I still had to tap out hard with brass rods and I know why now
The throat is really eroded and pitted.
I learned from this cast that I can get away with a much longer neck on the case which will allow me to run my bullet out longer.
why would I want to do that you ask? Well the way the tube feed system is on the Vetterli M78, the cartridge OAL must be a certain length within like 0.020" or it won't feed properly and you have to single load. The other thing is that with all the erosion, I can run the bullet much closer to where the rifling starts which with the erosion is way out there even beyond where my cast started. I am definitely NOT looking to eek out much accuracy out of this the way the erosion is. I will be using a load known good by other and much below the max based on Quickload that I just got in.

I want to see if I can use my borescope and try to measure where the Lands start on the rifling next.

with all the test casts and finally the .41 swiss, I think I"m comfortable doing other guns now. I'm liking using the heat gun. More controlled than the torch

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I make sure the barrel is at least at room temperature and even then use a heat gun to gently warm the part of the barrel that I want to take a cast from until its warm to the touch. Like a piece of metal that's been left next to a space heater to where you can readily feel the warmth soon as you grab it and it stays warm to the touch until you can spill the material and then let it cool together.
Dont worry too much about pouring enough in to where you can see the complete transition of the leade in. It'll come out as long as you don't try to extract it during the expansion period, clean properly and very lightly oil-follow instructions
That stuff is expensive once you start melting it down and making transfers with it so the tendency is to make small casts. Just be sure to order the smaller ingot next time and keep it in a can as you remelt for the next project.

Melnic · Feb 18, 2021

Archeryrob said:
Did you buy a pound or half pound of that stuff? How far does it go?

I'm going to try the lead and just go slow.

As mentioned in the first post, this was gifted. Incidentally before getting gifted, I had ordered some off brand from Amazon and its been lost in the mail for about 3 or 4 weeks now. I'm about to file a refund for it.

Melnic · Feb 19, 2021

After WEEKS stuck in USPS pergatory (not the vendor's fault) this finally arrived
https://www.amazon.com/gp/product/B00B1U540Y/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

melted down about 1/4 of the stick into a ladle and then put into the glock barrel I've been doing my process testing on.

Did 2 casts. I'll say this, these had to be punched out significantly harder than the cerrosafe which mostly pushed out by hand at the 30 minute mark.
Casts came out good though

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