cerrosafe castings do i really need it done?

[edadmartin]

id like opinions on cerrosafe casting. I get along with my Smith pretty well and understand also hes in business,needs to make a profit etc. he said my newly purchased 1992 marlin micro groove 336 in 30-30 should be both barrel and chamber cast to determine what size bullet to cast and col and head space.he mentioned that anytime you buy an older rifle its worthwhile to get castings done.to verify what you have, its not cheap. and the rifle will be R&R, and cast.plus all necessary action parts will be cleaned and polished barrel cleaned out too.
now that im writing this it seems worthwhile but at 160 dollars im cringing a bit,your suggestions??

[William Yanda]

Have you shot it yet?

[Wayne Smith]

Cerrosafe is available from Brownells and from Rotometals, both sponsors here. It is not hard to use, it melts at a low temperature. You can do it yourself if you have a kitchen stove or a propane torch and something to melt it in. It can be reused once you get measurements off it. It shrinks at a predictable rate and then expands at a predictable rate. Keep a record of when you cast it and the size related to your chamber is easily figured. Once you cast knock it out as soon as it hardens. It is literally easy. No point in paying someone else to do something this easy. Save money for what you can't do.

[shredder]

It is so easy to do your own chamber and throat cast. For a 336 lever gun in 30-30 I wonder why. Load up some lee 160 RN under 10 grains of Red Dot or something similar with a proven record in 30-30 and you should be good. I use the chamber and throat cast when things do not go as planned and I need some answers. I have never done it right from the start, though some will chime in to state the necessity of doing that. YMMV.

For 160 bucks , go get a good mould for that rifle and a can or 2 of powder to boot!!

[Yodogsandman]

Cerrosafe shrinks. You can just do a pound slug of your throat as described in the stickies. The pure lead slug won't shrink and will answer all of the same questions. Easier and much less expensive, too.

[runfiverun]

find the sticky on doing a pound slug [goodsteel started it]
this will tell you everything you need to know about your rifles throat.
and the measurements don't change over time.

[Tom Myers]

find the sticky on doing a pound slug [goodsteel started it]
this will tell you everything you need to know about your rifles throat.
and the measurements don't change over time.

This is a link to GoodSteel's post. It is in two parts so be sure to scroll on down a couple of posts to the second one.

http://castboolits.gunloads.com/showthread.php?218414-FYI-This-is-how-I-do-a-pound-cast (http://castboolits.gunloads.com/showthread.php?218414-FYI-This-is-how-I-do-a-pound-cast)

Below is a link to the Precision Bullet Design ~ Ultimate (http://www.tmtpages.com/#ultimate) help file for a slightly different method of a Chamber Impact Impression.

Chamber Impact Impression (http://www.tmtpages.com/draw/UltimateHelp/hs40.htm)

This following details a method of making your own hardwood slug mold for impact impressions.

Making a hardwood slug mold for impact impressions (http://www.tmtpages.com/draw/UltimateHelp/hs155.htm)


Another Link to some details of measuring Cerrosafe Chamber Casts.

Cerrosafe Chamber Casting (http://www.tmtpages.com/draw/UltimateHelp/hs30.htm)

Hope this helps.

[44man]

I have used the stuff many times and never got as accurate as pure lead. No matter how I timed it, numbers were always under size.

[matrixcs]

I have used the Rotometals chamber casting alloy with good results. There is a necessity to be paying attention to the time when measuring and casting..
According to Rotometals
Melts between 158 and 190 degrees Fahrenheit

Should be melted in a clean iron ladle without direct flame on the product.

The chamber being cast should be cleaned thoroughly and a thin coat of oil or graphite applied.

Reusable

Contraction expansion factor versus time, measured in inch per inch compared to cold mold dimensions. Test Bar x 10
2 minutes - .0004"
6 minutes - .0007"
30 minutes - .0009"
1 hour + .0000"
2 hours + .0016"
5 hours + .0018"
7 hours + .0019"
10 hours + .0019"
24 hours + .0022"
96 hours + .0025"
200 hours + .0025"
500 hours + .0025"

[Bent Ramrod]

Edadmartin,

Your own signature line answers your question. If the rifle is in sound condition (and your gunsmith can tell you that for a lot less than 160 scoots) you should be able to get all the data you need to have with the making of a dummy cartridge and twenty reloads using any flatnose .30 caliber cast boolit in the 150-170gr range and 0.311" diameter.

If you were buying a bench rest rifle, a wildcat or an antique of unknown caliber and provenance, maybe those operations would be necessary. But in your case, they aren't.

I have a bunch of "older" rifles and have done chamber casts on maybe three of the weirdest calibers and slugged the bores of about ten more. Unless I can't figure out the chambering to order loading dies, or encounter some accuracy problem in shooting, these measurements come under the heading of "too much information."

[MostlyLeverGuns]

For $160 you can pleasantly experiment with a lot of bullets! Tap a .310 or .315 round ball through the barrel if you want the diameter. Spend some of that $160 on a decent dial caliper. See how that .311 cast bullet chambers. BENT RAMROD has it right. I have ' bunch of old/older rifles', mostly 30 cal, I start with a .310 flat nose 160-180 grain gas check with 18-20 grains Rldr 7 or 4198 and go from there. Works for .30-30, .300 Savage, .303 Savage, .308 - Marlin 336's and Savage 99's. Maybe .309 or .311 might be better. 16 grains or 21 grains better than 17grains. 4227 or 2015 better than 4198? Only SHOOTING can answer these questions. There is a lot/tremendous amount of information on the .30-30 and reloading techniques for it. RELOADING and SHOOTING provide the answers, not chamber casts or bore measuring. Observe your results, on target and at the loading bench. You can enjoy that $160, OR your gunsmith can.

[edadmartin]

I agree that casting seems not necessary for this rifle after all.I did nt know it shrunk and accurite measurements depends on how long you wait after popping the casting, alot of variables having never done it my self.still seems not definitive enough to spend 160 bucks on.ill shoot my commercial rounds to see how she shoots, then slug the barrell and see what size bullet is needed,from everything ive read it will slug larger than .309, so ill have to be on the look out for a bigger mold than i have .
ill borrow a friends col guage,i think it a hornady, in fact ill watch him first .
great input from everyone,thats why i like the forum.

[Tom Myers]

I have used the stuff many times and never got as accurate as pure lead. No matter how I timed it, numbers were always under size.

44man,

I believe that the correction factor that is supplied with the Cerrosafe alloy is actually taken from an original test performed on a rectangular bar of fairly large size.
While correct for that particular size of bar, It sure does not work for smaller sized bullets.

After collecting many measurement values of different chamber casts taken at varying time intervals, I came up with a formula that seems to work quite well when applied to the data that I have collected.

Just out of curiosity, if you have an old Cerrosafe casting lying around, try this method and see what the results are.

I will use one of my several years old Cerrosafe castings of a Marlin 94 25-20 chamber that I had relined to provide an example.

Measure a diameter on the casting - I'll use the chamber neck as it is clean and free of the dings caused by quite a few years or being banged around.

My micrometer shows a measurement of 0.2788".

My records show that an impact impression made of the chamber resulted in a neck measurement of 0.2776"


25-20 Cerrosafe chamber neck measurement of 0.2788"
http://www.tmtpages.com/LinkSkyImages/Alloy/Cerrosafe%20calc%20neck.PNG

http://www.tmtpages.com/LinkSkyImages/Alloy/25-20%20ChamberSpecs.PNG


This is how to manually do the calculations.

Multiply the Cerrosafe measurement value by the Hours-Since-Cast
0.2788 x 1000 = 278.8
Multiply this value by 177.62
278,8 x 177.62 = 49520.456 = (value # 1)

Multiply the Cerrosafe measurement value by the Hours-Since-Cast
0.2788 x 1000 = 278.8
Multiply this value by 178.39
278.8 x 178.39 = 49735.132
Subtract 1 from this value
49735.132 - 1 = 49734.132 = (value # 2)

Now, divide value #1 by Value #2 to get the correction factor.

49520.456 / 49734.132 = 0.9957036 = the correction factor

Finally, multiply the Cerrosafe measured value times the correction factor.
0.2788 x 0.9957036 = 0.2776 = the actual measured value of the chamber neck from an impact impression of the chamber.


I measured the groove diameter on the Cerrosafe casting and this is the result of the calculations. (Not perfect but "Close enough for Government Work")

http://www.tmtpages.com/LinkSkyImages/Alloy/Cerrosafe%20calc%20groove.PNG

[edadmartin]

Love the comment " reloading and shooting provide the answers"
we live in an age of wikii and you tube.

We cant make a move until weve searched the net for truth,you cant start anything until you spend your dollars on unnecessary stuff,like a right of passage.
i continually have to remind my self to use the brain God gave me ,and do it my self. Let common sense and logic prevail, not the wallet. Confiring with a band of brothers in arms also never hurts.

[Char-Gar]

OK, truth telling time! Paying a gunsmith to do a cast is a waste of money and doing a pound slug is a waste of time.

The 30-30 Marlin MG barrels tend to run large in the grooves and lands and have a short or non-existant throat. Many cast bullet designs won't work well in these barrels. Fortunately there are some that will. Get a copy of Ranch Dog 165 grain gas check bullets, which was designed for this rifle. Lube and size it .311 and go shooting.

311407 Mod. as sold by NOE will also do well in your rifle.

That is all there is to this. No sense in making it difficult and esoteric. Many have gone on this road before and know the way.

[sghart3578]

OK, truth telling time! Paying a gunsmith to do a cast is a waste of money and doing a pound slug is a waste of time.

The 30-30 Marlin MG barrels tend to run large in the grooves and lands and have a short or non-existant throat. Many cast bullet designs won't work well in these barrels. Fortunately there are some that will. Get a copy of Ranch Dog 165 grain gas check bullets, which was designed for this rifle. Lube and size it .311 and go shooting.

311407 Mod. as sold by NOE will also do well in your rifle.

That is all there is to this. No sense in making it difficult and esoteric. Many have gone on this road before and know the way.


This plus 1.


SH

[44man]

Agree with Char-Gar too. My Marlin likes a .311" boolit and a .301 bore ride.
RD will work.
Good work from Tom too, I have timed the stuff to the second to get false readings.

[edctexas]

Cerosafe castings work well but... IF you screw up putting the liquid metal in the chamber you pay heck trying to get it out. In a semi-auto pistol, where the barrel comes out it is easy. Still if you wait too long for it to cool, it may get stuck in there.

I have tried several ways. There is a Sticky about doing a "pound cast". This is a great way for a non sophisticated shooter to measure the chamber, throat, and bore near the chamber. In most rifles, there can be a compromise between throat, freebore (if any), and bore dimensions. The pound case is a safe way to get all of that info. I would do a pound cast and spend your $ on lead, primers, and powder.

Ed C

[Hang Fire]

To each their own, but I much prefer the impact method using dead soft lead. Are you aware that Cerrosafe castings are only accurate within a certain timeframe after casting and will continue to change dimensions over time?

https://www.google.com/#q=impact+method+of+chamber+dimensions




id like opinions on cerrosafe casting. I get along with my Smith pretty well and understand also hes in business,needs to make a profit etc. he said my newly purchased 1992 marlin micro groove 336 in 30-30 should be both barrel and chamber cast to determine what size bullet to cast and col and head space.he mentioned that anytime you buy an older rifle its worthwhile to get castings done.to verify what you have, its not cheap. and the rifle will be R&R, and cast.plus all necessary action parts will be cleaned and polished barrel cleaned out too.
now that im writing this it seems worthwhile but at 160 dollars im cringing a bit,your suggestions??

[Outpost75]

Most .30-30 Marlins I have measured were sloppy in the chamber neck and in the barrel groove diameter.

If you have bullet sizing dies of various diameters, the easiest way to check is to assemble DUMMY rounds with FL sized case and sized bullets of various diameters, and try to chamber these in your rifle. I would bet money that your Marlin will probaby accept dummy rounds assembled with .311" diameter cast bullets without felt resistance, and that you will feel hard closure of the lever, resistance to action locking, and that the dummy upon extraction will show rubbing on a tight neck with .312" diameter bullets.

If I were to guess out of the blue the proper diameter for any Marlin .30-30 it would be .311". In the remote possibility that a dummy with .311 bullet chambers hard and shows rubbing on the neck, then you know to use a .310". In the equally remote possibility that it gobbles up a dummy with .312" bullet, try a .313" and see if you get resistance.

Fit the bullet to the chamber neck and brass wall thickness, NOT to the barrel groove diameter.

Use the largest cast bullet diameter which chambers and extracts in dummy rounds freely with NO resistance.

[JeffinNZ]

Speaking from a local point of view there wouldn't be a "gunsmith" within 500km I would trust to know what I required.

Go to the hardware store and buy some sulphur, melt it carefully and use it to make a chamber cast. Works great.

[runfiverun]

sulpher does work very well.
it's also good at cleaning your alloy, and will help pull zinc out if it's contaminated.

if I just bought a marlin 30-30 I wouldn't hesitate to find the ranch dog 165 mold and size/lube/check it to 311
and shoot it. looking for a MV in the 1900ish area.
if it showed any problems then I'd go looking for them..
if not then I'd continue shooting the combination looking for more accuracy.

[edadmartin]

just before i opened here i was checking out the NOE molds i found the 311165 rnfp GC (rd) now what is RD?
the 311407fn 170gr gc is looking good too.does it drop at .314 and then you size to .311? Of course ill slug the barrel prior.

[44man]

Ranch Dog, designed by a good and smart man here. He designed a line of boolits to fit better then others.
Sadly he does not offer the molds anymore since many were not up to his tight demands. But other mold makers make them.
Many are a TL design but I use regular lube like Felix on them. They sure do shoot!

[runfiverun]

the RD is ranch dog.
NOE is now doing re-pro's of the ranch dog molds.
LEE was making them for him, and he gave them his designs to use if they wished [they didn't]
but AL was smart enough to pick up on many of them.

anyway they were designed around the marlin rifles throats and getting across the goofy ball seat area marlin puts in their rifles. [or did, god knows what remlin does]
anyway Michael moved on from the Marlin rifles and now works with the Rossi model 92 lever guns.
or as I told him 'he finally seen the light' :lol:

[44man]

So sad lee could not meet specs but I was lucky with good ones.
We are so much in tune with cast and such good mold makers, life is good.

[popper]

I've not done a chamber cast of any kind for mine, did slug it. I recommend the 311 165 RD from Accurate, without crimp groove, normal lube grooves. With that boolit, all you need/get to play with is sized diameter and seating depth. It just works. NOE is off the shelf but Accurate will let you make changes and turn around is fast. Just get that boolit, most any rifle powder, load and shoot. No mess, no sweat, good results.
Edit: No need for the crimp groove in your 336. It gets in the way of seating depth which you need to adjust for YOUR rifle chamber.

[blackthorn]

Another vote for sulfur, but with about 15 to 20% graphite powder added.

[Hannibal]

To the OP - I believe you can certainly make your own chamber cast using either cerrosafe or the pound cast method. No matter who makes the castings, it will take time to do correctly. This will produce a bounty of useful information. And if I understand correctly, there was some action work to be performed as well?
At the end of the day, I would say it depends on weather you prefer to spend your own time and resources doing the work, or pay someone else to do it for you and who presumably guarantees his/her work if a mistake is made.

[Char-Gar]

To the OP - I believe you can certainly make your own chamber cast using either cerrosafe or the pound cast method. No matter who makes the castings, it will take time to do correctly. This will produce a bounty of useful information. And if I understand correctly, there was some action work to be performed as well?
At the end of the day, I would say it depends on weather you prefer to spend your own time and resources doing the work, or pay someone else to do it for you and who presumably guarantees his/her work if a mistake is made.

A degree in electrical engineering is not needed to turn on a light switch.

[HangFireW8]

$160 is a lot of money, if you find a little soft lead you can find out all you need to know by pounding a slug and taking a few bullet jam measurements with dummies.

I take a different view from many here, concerning loading completely in the dark. My first, and still primary cast boolit platforms are an 8mm Mauser, an old Colt 1911A1 45, and an FN 30/06. The Mauser turned out to be .325" (not .323") and .327 at the muzzle, the 1911 .452x.454" (oval bore, not .451"), and the FN was a perfect .3100" (not .308") in the grooves. I suffered from mysterious leading in the .45 and poor accuracy in the FN until I slugged both. The Mauser I slugged from the beginning and knew what I was getting into. Since buying a new 1911 barrel, sizing my /06 loads at .310 to .311", cutting 4" off the barrel and lapping out one 8mm mold and buying Lee 8mm Karabiner and Maximum molds, I've achieved accuracy without leading in all 3.

So no, I'm not keen on the idea of just-try-and-see, since my time is precious. It might work, it might not. I slug everything I intend to load with cast. You're free to find your own way, but I would take the time to slug the barrel. I do it 3 ways, throat, through and muzzle. If you have to do only one, if it's ex-military do the muzzle, everything else do the throat. Most war surplus rifles have bad cleaning rod wear near the muzzle.

[Ballistics in Scotland]

There are occasions when $160 for a gunsmith's examination can be a great bargain - authenticating a valuable antique before purchase, say, or safeguarding your anatomy, although if you listen to him in the latter case, you may never know he was right. But it would have to be a very detailed examination indeed - more than you need for a modern Marlin - to be worth that much, and let's not talk about its being just for the chamber case. Even if he has to read up on the subject and order the stuff in, you can do all that.

Shrinkage isn't a big issue unless you are too busy to measure it in the first hour or so, and in that case you can remelt it and do it again. Anyway, in a modern Marlin a ringed or pitted chamber is what you have to worry about, not exact dimensions, and the cast will surely show up that. If it gets into the wrong places it is harmless for anything that you can put in nearly-boiling water, as Cerrosafe melts at about 160 Fahrenheit. You can do an extremely good cast with sulphur, but beware of overheating it until you get a blue flame on top. That is very unlikely to produce a general conflagration, but the resulting vapour will cause rust on nearby steel objects it condenses on. Car body filler is also good, but you will feel a fool if you forget to lightly oil the chamber.

There is one reason the Micro-groove Marlins might be worth doing a cast or bore slug on. The original patent of 1953 didn't actually specify shallowness, which had been done before, but only angled sides to the grooves and five grooves per tenth inch of barrel diameter. But the accompanying drawing showed grooves only .015in. in depth for .30 caliber, and I think the rifling in early production was at least very similar.

171267

This was the kiss of death for their Model 322 in .222 Remington, which was phenomenally accurate when new, but eroded very quickly. Even in the more forgiving .30-30 it probably gave rise to most of the stories of low barrel lift and great sensitivity to bullet diameter. All the Micro-groove Marlins except the .22 rimfires were modified to a considerably deeper but otherwise similar version in 1968. So the bore of a fairly old Marlin is worth checking out.

[Hannibal]

A degree in electrical engineering is not needed to turn on a light switch.

Regardless of the task at hand, a gunsmith has an overhead to maintain. If the OP is not comfortable performing the task him/her self, then it is not reasonable to expect the 'smith to reduce his rate due to the simplicity of the task. His time retains it's value regardless of the job, IMHO.

[44man]

About every Marlin or Remlin I have measured has grooves .003" deep, even the Ballard. Micro groove just needs fatter to stop skid.
The most accurate .22 I ever owned was the 39 Mounty until the barrel got loose in the receiver, slide fit I could have fixed. It shot to opens but not to the scope on the receiver. That thing would do 3/4" at 100.
I had an original 1892 25-20 that did 3/4" at 100 with cast and opens.
I had a .35 Rem that did 1/2" at 100 with "J" words but would not shoot cast but I did not know the cast was too small. Old Lyman mold.
But Cerrosafe castings can give you false readings.
Pure slugs will always be best.
Cerrosafe is good to see throats or to find the caliber for a gun not known.

[HangFireW8]

All the Micro-groove Marlins except the .22 rimfires were modified to a considerably deeper but otherwise similar version in 1968. So the bore of a fairly old Marlin is worth checking out.

It's not a fairly old Marlin with early shallow rifling. It's a 1992.

[edadmartin]

Great info . I told the smith that i was going to shoot it and slug it before doing anything else with him just cant do 160 buck.thanks for all the info.