Casting- Weight of Lead Question

[giggitygiggity]

Hi, I have been reloading for years and have been researching casting recently. I understand the basic principles as they relate to getting lead, heating it, adding wax, scooping off impurities. My question is, what issues are there if you take a hunk of lead and all you know is that it is mostly lead. You can heat it up and scoop off impurities, but the molten metal is not going to be 100% pure lead and therefore, it will not be the exact weight for the bullet that you need.

For instance, the molten mixture might have some metal that weighs more than lead so the 230gr .45 bullet that you plan to make might end up being 235gr as a result or maybe 225gr if it contains metals lighter than lead. Perhaps the impurities get scooped off and any remaining metals contribute so little to the remaining weight that it is negligible, but I am curious.

Perhaps I'm overthinking it, but can someone shed some light on this issue?

Additionally, I see bullet molds for .451, .452, etc. what determines the size that I want if I am making .45ACP or any other bullet for that matter? I've heard that lead casts should be .001 larger that FMJ equivalents in order to allow the lead to adhered to the rifling when fired.

Lastly, how can you cast rifle bullets that are to be shot at supersonic speeds?

I'd love to hear any tips, tricks, and pieces of advice that you might have. Thanks!

 

[Blue68f100]

I don't cast but, bullet weight from a mold is based on a allow mix of zinc and tin added to lead. The best way is running a BHN on the current lead to get an idea of purity. Pure lead will cast heavy.

 

[Schwing]

The bullet weights are usually slightly different with different alloys but it is usually a very minor variation (I would estimate 2-3%). Even so, I work up new loads for every batch of alloy that I use. It seems extreme but I want them to be as accurate as possible. I also order my lead in huge batches so I don't have to deal with it as much_

Hardness is more of an issue than weight. Differing amounts of tin and antimony in an alloy change both the hardness and the viscosity (how well the alloy fills the mold) as well as the alloy melting point. This can get kind of in depth so I would recommend the Lyman 49th edition to get started. It is a pretty quick read but will get you the info you need to understand this.

Diameter is probably even MORE important than hardness. Normally you would want to slug your barrel to find its diameter and then cast/size bullets that are a minimum of .001 larger in diameter. This prevents gas cutting that causes leading and poor accuracy. Barrels can vary a large amount. I have 9mms that are .355 in diameter and others that are .359! Shooting a bullet sized at .356 or even .357 down a .359 barrel is a recipe for leading and tumbling bullets.

Personally, I don't cast for any rifle calibers except the 45-70. For those that do, gas checks can be added to the bullets to give them accuracy and no leading at higher speeds.


There is so much information out there on this topic that I won't even try to cover more. I REALLY recommend lymans 49th.

 

[Schwing]

I also forgot to add this. Glen E. Fryxell and Robert L. Applegate wrote a free book that covers almost all of the basics. This was a great read:

http://www.thehighroad.org/attachment.php?attachmentid=205018&d=1416109868

 

[John3921]

Lead is the heaviest metal you're going to find in your alloy. The two other metals used in varying amounts are Antimony and Tin. Lead has a density of 11.342 gm/cc, Antimony is 6.684 gm/cc, tin is 7.287 gm/cc.

There is a summary of various casting alloys and their composition here: Casting alloys

Avoid contaminating your lead with zinc. You can ruin your entire batch of lead with just a bit of zinc. Since a lot of wheelweights are now made of zinc you have to be very careful in sorting them.

 

[Wildfire]

Casting.

Ok, here goes. I cast some 255 grain bullets that came out to 254 grains on the scale. 1 grain is not an issue. That was wheel weights. Now, You will get a lot of dross from wheel weights. They are dirty and have a lot of steel parts. Still not an issue unless you want to buy casting alloy that would come much cleaner. Wheel weights will toss bullets right around a hardness of 9 to 10 on the tester. If you plan to get into this big time a hardness tester would really come in handy. Read your books on testing so I do not have to detail that. It matters.

My molds are .453" I then run them through a luber that is also a sizer and they come out at .452 with lube in them. There will be those who do this different.
Most jacketed rounds will be sized at .451". But, lead rounds are fine at .452 or even at 453" in a .450" barrel. Lead bullets do not increase PSI much if at all.

The "scopper" you use to clean off dross must be pre heated. If not, you will learn very fast a hard lesson. Any cold metal entering that Hot pot will cause an upset and blast hot metal all over you and the room you are in. You will only forget this once. A hardness of 10 is more than OK for any .45 caliber rounds.

Casting for higher speed rifle will require extra hard metal and it gets pricey. You can only go just so far with that.
Pure lead does not cast well at all. It must have tin to cast and get a decent bullet. But, if you have been studying up on casting you know that already.

Hand casting can be fun and yet a lot of work. I have a magma caster and that took a lot of pain out of it. It has cast hundreds of thousands of bullets. My Star luber works very well and is fast also.
Cast bullets harden with time. Testing freshly cast bullets tells you very little.
Once you get into this you can tune your bullets hardness to do what ever you want. Magnum loads or mild loads. I have found that the harder bullets are as a rule not as accurate as the softer ones. At a hardness of 10 I find little to no leading. I have found factory bullets that do not stay uniform in weight.

 

[Wildfire]

BTW
Magma Engineering company has a very good book on casting.
602-969-3122

 

[USSR]

Yep, you are definitely over thinking it.

...what issues are there if you take a hunk of lead and all you know is that it is mostly lead. You can heat it up and scoop off impurities, but the molten metal is not going to be 100% pure lead and therefore, it will not be the exact weight for the bullet that you need.

First, while you will have some lead of any unknown composition, try to buy lead of a known composition such as wheel weights, lead pipe/sheeting, and linotype. Then, just add a little of the unknown composition lead to the mix so that it will be diluted and not have a big impact on the alloy result. Second, if the bullet is 225gr or 235gr instead of 230gr is not very important. Seating depth of the bullet is likely to have a bigger impact than minor weight fluctuations.

I see bullet molds for .451, .452, etc. what determines the size that I want if I am making .45ACP or any other bullet for that matter? I've heard that lead casts should be .001 larger that FMJ equivalents in order to allow the lead to adhered to the rifling when fired.

Just because a bullet mold is advertised as a particular size, does not mean your bullets will come out that size. The alloy you use will help determine that. If you use an alloy that has little antimony and tin and is soft, your bullets will be heavier and smaller in diameter than if you use an alloy that is hard with a lot of antimony and tin. Yes, for handguns you typically want bullets with a diameter of .001" over bore size. So, for .45 ACP you want your mold to produce bullets of .452" or larger and then size them to .452". Remember, it's really tough to size .451" bullets to .452".

...how can you cast rifle bullets that are to be shot at supersonic speeds?

If you size them to .002" over bore size and use a linotype alloy, you can fire them up to about 1800fps. I shoot such cast bullets at full velocity out of my M1 Carbine all the time. Hope that helps.

Don

 

[243winxb]

Bullet Sizes & Weights – How to Vary Them
The bullet diameters and weights presented in this list are based on the use of Taracorp’s Lawrence Magnum bullet alloy (2% tin, 6% antimony, 1/4% arsenic, 91.75% lead).

Bullet diameters and weights will vary considerably depending on the lead casting alloy used. This variation can be as much as 1/2% on the diameter, and 8% on the weight among the most commonly used casting alloys. For example, a .358-158 grain bullet might show a diameter variation of .002", and a 13 grain difference in weight.

Of the most commonly used alloys, wheel weights (.5% tin, 4% antimony, 95% lead) will produce bullets having the smallest diameter and heaviest weight, with such bullets running approximately 1/3% smaller in diameter and 3% heavier than bullets cast with Taracorp's metal. Linotype will produce bullets with the largest diameter and lightest weights. This alloy will produce bullets approximately 1/10% larger and 3% lighter than Taracorp. Other alloys of tin and antimony, with antimony content above 5%, will produce bullets with diameters and weights falling between those cast f rom wheel weights and linotype.

Alloys containing little or no antimony will cast considerably smaller than wheel weights and in some cases will produce bullets too small for adequate sizing.

Within the limitations given above, the weight and diameter of a cast bullet can be adjusted by varying the
alloy’s antimony content.

The size and weight of bullets of a given alloy will also vary according to casting temperature. Higher temperatures will result in greater shrinkage as the bullet cools, thereby producing a slightly smaller and lighter bullet than one cast of the same alloy at a lower temperature.

http://www.redding-reloading.com/online-catalog/88-bullet-moulds-charts I just add linotype if i want harder and larger in diameter.

 

[gwpercle]

You are overthinking it.
Casting and bullet alloys , sizes and any of a hundred different variables can get you confused really quick. Reading all the postings on the net can confuse you even more.
Look at Schwing's post and click on Fryxell and Applegate's book. Make it and Lymans Cast Bullet Handbook , 4 th Edition is in print and the 3 rd Edition if you can find it...make these your Bibles when it comes to casting.
Everything can be done 9 different ways and you will go insane listening to them all , just stick with these guides until you get experienced .
Gary

 

[Conservidave]

These are some of my Hi-tek coated (.356 125grn) 9's from range scrap. The lead is really soft but drop right at .356 and weigh in at 127grn. The range lead really does need some linotype to increase hardness but the coating and Mdie makes them work just fine.

 

[Wreck-n-Crew]

I don't cast but, bullet weight from a mold is based on a allow mix of zinc and tin added to lead. The best way is running a BHN on the current lead to get an idea of purity. Pure lead will cast heavy.

Zinc? Uh you got problems if you have zinc in your mix....and a bhn does not equate to a purity or of mix percentages and metals.

There are metals that blend with lead bullets and often found in lead bullets in minut percentages other than tin and antimony but of those zinc is NOT what one would call lead bullet alloy friendly.

zinc is not like tin, where in small amounts affect the mixture in a positive way.

Antimony adds hardness alone. Tin adds a small percentage of hardness and allows lead to flow smoothly and prevent poor fill. Also tin when mixed with equal amounts of antimony will increase the hardening ability of the antimony in the alloy.

In fact adding more tin past just 2% ( maybe as high as 4%....maybe i need to keep better notes...) adds no more hardness to lead alone. It( tin) and antimony complement each other when looking for a hard lead alloy. Adding equal amounts of each tin and antimony create a harder mixture for less.

http://www.lasc.us/castbulletalloy.htm

I think you mixed antimony up with zinc maybe?

I don't cast but, bullet weight from a mold is based on a allow mix of zinc and tin added to lead. The best way is running a BHN on the current lead to get an idea of purity. Pure lead will cast heavy.

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[X-Ring]

Lastly, how can you cast rifle bullets that are to be shot at supersonic speeds?

You use a gas check. A small copper cup applied (pressed on) to the base of the bullet.

 

[Bula]

Start skimming as the lead becomes molten. The zinc weights, which you want zero part of, will float along with the clips. I cast stick on weights with clip on weights. I do have Lino and 60/40 tin ingots. I'll typically add 4 pounds of Lino and and 2 of the 60/40 to about 94 pounds of mixed wheel weights. Good alloy for me, pistol or rifle. And they cast good looking bullets.

 

[homatok]

With cast, FIT IS KING! So----start by slugging your bore and then plan to make your bullets one to three thousandths over the slugged size. No one can tell you what size is “best”, because each firearm is an individual and what works in mine may/will not likely work in yours (barring a happy coincidence).
More that 2% tin in your alloy is a waste. Never let the tin content exceed the % of antimony in an alloy. Wheel Weights (as noted) run about 8 to 10 BHN, but the BHN can be increased by heat treating. This can be accomplished by dropping the bullet from the mould into a bucket of cold water, or heating the bullets for about 1 hour at just below the slump temperature of the alloy and then quickly dropping the bullets into cold water.

Shooting cast at high velocity is an advanced undertaking and requires some knowledge beyond the entry level. I would suggest you log onto the “Cast Boolit” site and do a search for posts by Larry Gibson, Sargent Mike, Bjorn, Goodsteel, Loyd Smale and there are many others over there who are very knowledgeable. The books recommended above are excellent resources. If you go to the Cast Boolit site, read the stickies’ at the top of each section. I doubt there is a question on casting that has not been answered many times over there.

 

[snuffy]

I don't cast but, bullet weight from a mold is based on a allow mix of zinc and tin added to lead. The best way is running a BHN on the current lead to get an idea of purity. Pure lead will cast heavy.

Then may I suggest you NOT answer questions about casting. ANY zinc in bullet casting alloy will ruin it, period!

Boolit weight is primarily controlled by the shape of the boolit. Another consideration is what alloy is expected to be used to cast with. Size of the cast boolit is also part of the design of the mold. Most molds are cut with a "cherry". A cherry looks like the boolit with teeth. It is spun while the mold is moved into it, cutting the cavity.

Most boolits have to be sized. They are intentionally cast oversized, to be sized down while lube is also squeezed into the lube groves. A new process is gaining popularity with casters, the application of polymer coating using static electricity to apply the coating as a powder. Then the boolit is baked to melt and harden the coating. This makes the outside diameter of the boolit bigger, so it is sized down. No other lube is needed, they're loaded as is.

Start skimming as the lead becomes molten. The zinc weights, which you want zero part of, will float along with the clips. I cast stick on weights with clip on weights. I do have Lino and 60/40 tin ingots. I'll typically add 4 pounds of Lino and and 2 of the 60/40 to about 94 pounds of mixed wheel weights. Good alloy for me, pistol or rifle. And they cast good looking bullets.

NO! You wait until the lead is all melted and is at least 700 degrees BEFORE you FLUX ,,-- THEN skim the dross, clips, valve stems, and any other debris off the surface of the molten lead. FLUX can be anything that contains carbon. Wax, old oil, cooking grease all will work. BEWARE it will self ignite in a flash if you're at or above 700 degrees. Wood sawdust is the absolute best fluxing agent. Gather some up around your skill saw, dump about a cup on a 100 pound pot, let it char, then stir the black charred wood into and through the molten lead.

One more tip, zinc melts at 787 degrees, keeping the melted lead under that temp will make the zinc wheel weights float on the surface to be skimmed off.

Notice how many times I mentioned temperature. A lead thermometer is almost a required tool. Without it you're guessing, that can lead to accidentally melting zinc into your alloy. If that happens, all that lead is good for is sinkers or ballast.

 

[silicosys4]

I don't cast but, bullet weight from a mold is based on a allow mix of zinc and tin added to lead. The best way is running a BHN on the current lead to get an idea of purity. Pure lead will cast heavy.

You never want zinc in your lead. Antimony and tin is good, zinc is bad.

 

[Blue68f100]

Zinc? Uh you got problems if you have zinc in your mix....and a bhn does not equate to a purity or of mix percentages and metals.

There are metals that blend with lead bullets and often found in lead bullets in minut percentages other than tin and antimony but of those zinc is NOT what one would call lead bullet alloy friendly.

zinc is not like tin, where in small amounts affect the mixture in a positive way.

Antimony adds hardness alone. Tin adds a small percentage of hardness and allows lead to flow smoothly and prevent poor fill. Also tin when mixed with equal amounts of antimony will increase the hardening ability of the antimony in the alloy.

In fact adding more tin past just 2% ( maybe as high as 4%....maybe i need to keep better notes...) adds no more hardness to lead alone. It( tin) and antimony complement each other when looking for a hard lead alloy. Adding equal amounts of each tin and antimony create a harder mixture for less.

http://www.lasc.us/castbulletalloy.htm

I think you mixed antimony up with zinc maybe?



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Your right, I had one of those senior moments.

 

[Wreck-n-Crew]

Your right, I had one of those senior moments.

I have them too...lol

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[Bula]

Quote:
Start skimming as the lead becomes molten. The zinc weights, which you want zero part of, will float along with the clips. I cast stick on weights with clip on weights. I do have Lino and 60/40 tin ingots. I'll typically add 4 pounds of Lino and and 2 of the 60/40 to about 94 pounds of mixed wheel weights. Good alloy for me, pistol or rifle. And they cast good looking bullets.

NO! You wait until the lead is all melted and is at least 700 degrees BEFORE you FLUX ,,-- THEN skim the dross, clips, valve stems, and any other debris off the surface of the molten lead. FLUX can be anything that contains carbon. Wax, old oil, cooking grease all will work. BEWARE it will self ignite in a flash if you're at or above 700 degrees. Wood sawdust is the absolute best fluxing agent. Gather some up around your skill saw, dump about a cup on a 100 pound pot, let it char, then stir the black charred wood into and through the molten lead.

I guess I did mistate the skimming part. Lead melts at about 620 ,or so. I sift clips and unmelted weights as soon as I'm dealing with liquid lead. I didn't even mention fluxing. Then I flux, a few times. I like wax, as my wife saves all her candle nubs for me! I don't use a thermometer, so I figure I'll just sift out any zinc weights far before I hit their melting temp to play it safe. More than one way to skin a cat I guess...

 

[gojuice101]

Alloy can definitely affect boolit weight, but it is usually not enough of a difference to matter. It also depends on other factors. I've cast rifle bullets using a 170gn mold that come out at 165gn, and used a 120gn 9mm mold that come out at 120gn on the dot. Same pot of alloy, and cast in the same session. Don't know what the difference is, but either way +/- 5gn isn't enough to concern me, with my loads. Others might be different.

As far as casting fast rifle boolits, I have run gas checks and different lubes in the past. Now I just powdercoat. I've seen people push boolits to 2500fps using plain lead (uncoated) and gas checks. No idea what lubes were used, but it can be done. Personally, I hate messing with gas checks, so I avoid them.