Resizing and Work Softening

[rjathon]

I've read that sizing bullets work softens the lead. I am curious about how much hardness one loses and how various alloys are effected. Also how does it effect water quench COWW bullets.

Does the more that you size down increase the effect? How many thousands can one size down and get good results?

Is it wise to start with bullets that are too hard so that they will soften to the appropriate level after sizing.

Also how soon after casting should you do your sizing?

Thanks

[facetious]

The work softening is on the surface only and I do not think go's to deep. What I do now when WDing is to size them in a Lee push through die with in a few hours after casting that way thy age harden all the way through. Then when using them later I can run them through the lube/sizer to lube them with out sizing them.

The NRA cast bullet book had some stuff on this and if I recall it didn't mater much.

[scottfire1957]

Think about how much of the bullet is "worked" when put through a sizer. Just the driving or other bands, only on the surface, and only for a fraction of a second. They get worked harder going down the barrel, we don't "overharden" to compensate for that.

Then consider that cast bullets with hardening metals added "age harden" for a while.

As in the previous response, cast, cool, size, let 'em harden.

[tazman]

I resize within an hour after casting. I water drop for better hardness. It takes a water dropped boolit a few days to harden completely. Mine continue to harden after I resize. I have checked the drive bands where the sizing took place and they seemed to be the same hardness as the rest of the boolit after 3-4 days.

[Wayne Smith]

I don't have a hardness tester, but from what I've read here and on the off chance that these guys are right (yeah!) I size/lube within 12 hrs of water dropping. usually within a couple of hours, but definitely within 12.

[Ballistics in Scotland]

I think a thin outer layer of lead tends to be harder than the inside of the bullet, something a hardness tester is unlikely show clearly. This would be "free" hardness, which unlike a harder alloy won't impede the ability of the bullet to upset and seal the bore. If sizing scrapes away metal, it is much more likely to remove hardness than if it just squeezes the bullet down.

If this matters, I wonder if some kind of roller sizing device could produce improvement? Personally I think leading is much more dependent on friction and melting point, and expansion on game depends on hardness throughout the bullet.

[MBTcustom]

I have not experienced this.
I have shot WQ, bullets with or without sizing, and I can see no difference between them.
I have tested sized and unsized bullets for hardness, and I can see no difference between them.
I have sectioned a bullet in the milling machine after testing the surface for hardness, and then checked the hardness in the middle of the bullet with no observable difference.
I see people recommend not sizing in order to not soften the surface........so that it can be sized by the barrel anyway.


I also see people who size bullets thereby changing the way they interact with the rifling. Sometimes this is what the gun wants, and sometimes not.

Those who it helps conclude that they have improved accuracy by making a more perfectly round bullet and they are wrong.

Those who do this and see accuracy degrade conclude that there was this immeasurable, undetectable, surface of hard material on the surface that they destroyed by sizing, and they too are wrong.

The he truth is that bullet hardness and size work hand in hand to produce WALL PRESSURE that helps the bullet spin, helps it stop up the gas behind it, and helps it accurately translate your barrel quality into groups downrange.

Wall pressure is what you are after. You can use a soft bullet and make it oversize, or you can use a hard bullet and run a little closer to groove diameter, but at the end of the day, what you're after is the right amount of wall pressure and that has nothing to do with an immeasurable "hard skin" that means nothing anyway, because it's only as strong as the material backing it up.

I mean seriously, if the "skin" everybody talks about is so thin and fragile that it cannot be measured with a tiny bit of pressure from a hardness tester, how's it really going to amount to a hill of beans when it's getting shredded by your rifling at high speed? The line of thinking that claims this theoretical "hard crust" exists and has effect on the bullet's performance doesn't seem logical to me at all.

[Mal Paso]

goodsteel, that's too much common sense for me to take in all at once. I'm going to have to sit down.

[facetious]

When a boolit is hardened, it is hardened all the way through not case hardened.

[Ballistics in Scotland]

I think it depends on the alloy. Antimony has a tendency to form a tiny lattice of hard metal crystals on the surface, but tin doesn't, and pure lead just sits there. That lattice structure, hard but still capable of leading, is why we don't harden our bullets with antimony alone, although it is cheaper for us and cheaper for the wheelweight manufacturers.

I think the argument for reducing hardness by sizing is all very uncertain and not of great importance. But I don't believe the inability to show any such hard layer with an ordinary hardness tester proves much. Anodized aluminium is coated with a layer of oxide harder than any metal, and there is a much thinner layer on any aluminium, but they don't provide any resistance to speak of in testing or accidental denting.

[Wayne Smith]

After reading Tim's article the third time it dawned on me that I lube/size right after water dripping them because it is easier on the sizer and on me to do it that way! Sizing hardened boolits is not easy.

[MBTcustom]

Anyone can test my opinion for themselves and see if it's true or not. All you need is two identical molds, (one that casts bullets .002 bigger than the other) and a common sizer to pass both of them through but only one of them actually gets sized down any significant amount.
Size one, and just pass the other through the die. Use several alloys to conduct this test (or just have the molds made in a size you really like to shoot like 311466 as I have) and observe if there is any consistent difference between the two of them, assuming both were passed through the same sizer.

Surely if this immeasurable, ultra important, theoretical layer of antimony rich skin (which doesn't show up in XRF tests either when the core is compared to the surface) is really all that important, it will manifest itself in a constant and consistent manner. If it does not, then it either doesn't exist in any viable form that is important, or there are other things that matter more that are not being payed any attention because the shooter is blaming the ill effects on some ethereal "hard skin" that looks good on paper.
You may simply be "hammering nails into trees".

Speaking of hammering nails into trees, all my friends know what it means when I use that expression, and here is the meaning of it:

I once had the opportunity to take a tour of a saw mill by a wise forester who ran it. He showed me all different species of wood and some of the interesting things he had found lodged in the middle of trees. He made the comment that he abhors cutting up pecan trees though, and he will not run pecan through his mill unless the customer agrees to pay for his blades.
I found this curious, and told him that I had carved pecan wood before, and never noticed any inordinate dulling of my tools?
He said it's not the wood itself that causes him trouble, it's all the thousands of nails lodged in the tree that tears up his blades. He went on to explain that at one time, when a pecan tree would not bear a good crop, it was thought that the tree was "low on iron" and the solution was to hammer a handful of 16 penny nails into the tree to "give it the iron it needed". Sure enough, the nail ridden tree would begin to bear pecans by the bushel basket, which reinforced the notion that the tree was low on iron and the practice continued for years.

At one point however, a young biologist was passing through the area and noticed this absurd behavior. He spoke to the locals about it, and asked them why in the world they are hammering their pecan trees full of nails with wild abandon? The foolish biologist was then educated about the tree's need for iron, and told "not to be so foolish and simple minded!" "There's obviously more going on here than is taught in your textbooks sparky!".
To this the biologist asked if they ever prune the pecan trees? The locals had never heard of such a thing. He then explained that by hammering nails into the tree, they were merely stressing the tree nearly to death (same thing as pruning) and the tree tried to reproduce itself by bearing more fruit.

So this is why there are thousands of pecan trees with trunks full of nails, but people are people, and they do this sort of thing all the time.

Curious eh?

[243winxb]

http://www.freepatentsonline.com/5464487.html Go to bottom of page. Oven heat treating is not the same as water droping from the mold. See LYman's FAQ about making bullets harder.
Q: Is there anything I can do to make the bullets harder?
A: Cast bullets can be heat treated to increase their hardness providing your alloy has some antimony present. To heat treat your bullets: Cast your bullets in the normal manner, saving several scrap bullets. Size your bullets but do not lubricate them. Place several scrap bullets on a pan in your oven at 450 degrees and increase the temperature until the bullets start to melt or slump. Be sure to use an accurate oven thermometer and a pan that will not be used again for food. Once the bullets start to melt or slump, back off the temperature about 5 to 10 degrees and slide in your first batch of good bullets. Leave these in the oven for a half hour. Remove the bullets from the oven and plunge them into cool water. Allow them to cool thoroughly. When you are ready to lubricate, install a sizing die .001" larger than the one used to initially size them. This will prevent the sides of the bullets from work-softening from contact with the sizing die. Next apply gas checks if required and lubricate. These are now ready for loading.

[MBTcustom]

http://www.freepatentsonline.com/5464487.html Go to bottom of page. Oven heat treating is not the same as water droping from the mold. See LYman's FAQ about making bullets harder.

It's true that he said things. What he said is not necessarily true.
For instance (taken from the same article):

Cast bullets, whether commercially or handloader produced, also suffer several additional disadvantages. One such disadvantage is the fact that the cast bullet has a seam from the molding equipment. Such seams reduce the aerodynamic qualities of the bullet and, therefore, reduce the bullet's accuracy if it is to be fired in an unjacketed condition.

Another disadvantage of the casting method is that an alloy is typically used which contains a considerable quantity of tin as previously mentioned. Tin is added to enhance the flowability of the molten alloy in the mold, and if tin is not included, the resulting molded product is usually inferior. However, the tin tends to reduce the hardness of the product and the effectiveness of the antimony which has been included for that purpose. Thus, the level of antimony must be increased to compensate for the loss of hardness.

The lower the hardness, the greater the amount of leading that is deposited in the lands and grooves of the firearm rifling. Increased leading reduces the accuracy. Moreover, as the muzzle velocity of the ammunition increases, the leading also increases.


As previously mentioned, leading is a function of the muzzle velocity of the bullet.

Leading of an unjacketed bullet typically occurs when the muzzle velocity is about 900 fps or more

Moreover, the tendency of jacketed bullets to increase barrel erosion and shorten the life of the barrel is substantially reduced because the need for jacketing is eliminated.

the hardness of the bullet may be substantially increased to a hardness of 25-30 Brinell where the metal of the bullet is an alloy of lead and about 3.5 wt % antimony. A reduction in the amount of antimony from this amount will result in some reduction in the hardness, but even when the antimony is eliminated altogether, hardnesses may be substantially increased in the swaged wrought bullets of the invention.

Well written doesn't mean well researched or understood.

[Ballistics in Scotland]

Well written doesn't mean well researched or understood.

Indeed it doesn't. Where he really lost me was when he said jacketed bullets produce erosion. They don't. They might produce more mechanical wear, though it won't be much, and if not completely consistent along the bore's length, it will be greatest where the bullet is fastest. It would be good for a barrel in the unlikely event that it could be detectable.

Of course leading is a function of muzzle velocity. But it is also a function of numerous other things, of which the ordinary user with a sensible velocity target is more likely to fall foul.

[243winxb]

The article should also say, swaged bullets are more accurate than cast bullet. :guntootsmiley:

[MBTcustom]

Indeed it doesn't. Where he really lost me was when he said jacketed bullets produce erosion. They don't. They might produce more mechanical wear, though it won't be much, and if not completely consistent along the bore's length, it will be greatest where the bullet is fastest. It would be good for a barrel in the unlikely event that it could be detectable.

Of course leading is a function of muzzle velocity. But it is also a function of numerous other things, of which the ordinary user with a sensible velocity target is more likely to fall foul.

Actually, I would take issue with your last statement. Leading is a cause of pressure and the velocity is merely a byproduct of it. If the pressure behind the bullet becomes great enough to compromise the seal the bullet has on the barrel, leading will occur no matter what the velocity is. As I have said before, preventing leading and maintaining accuracy is the result of carefully managed wall pressure.
I say this as someone who has personally fired WQ COWW alloy with a very specific amount of tin added, to over 2800 FPS in the XCB project with no trace of leading.
Not that I mean to argue, I'm just saying that everything I have seen and proven kind of makes that dude sound like a guy selling ice to the Eskimos.

[vzerone]

I'll start off with I was told when I was youngster that if you pound a copper nail into a tree that it will kill. Never tested that theory, never looked it up, so don't know how true it is.

I know that when you heat treat a bullet either by WQ or oven heat treating that they harden all the way through. I cannot see how one can get a good hardness test on a bullet they section because just sectioning it changes it. Pounding bullets with a heavy hammer on an anvil is a crude test, but it will show you if a bullet is harder then another. If you have one that has just the outer skin hardened as some claim I can assure you that is no resistance to a heavy hammer. Even after you initially hammered the bullet the outer skin no longer exist when you have pounded it into a thick coin. No, they harden all the way through and that is why oven heat treating is better and produces a harder bullet then WQ'ing.

Depending on your alloy it takes bullets some time to age and grow harder and larger too. More then two day. I've done extensive testing of shooting bullets at different days of aging and again can assure you that there is a difference. You have to have a few things to perform that test and two of the most important ones is having a very accurate rifle and being a good shooter.

I've also done extensive testing of shooting bullets of the same caliber, design, and alloy and can also assure you that there is one size that a rifle barrel will prefer on that particular rifle. I believe one of the places that sizing a bullet doesn't help it was from the NRA. It's also pretty hard to out shoot a swaged bullet. If someone doesn't believe bullets age, with the right alloy get harder, and that it doesn't matter if you shoot them very early after casting them, apparently hasn't had bullet grow so large that they had to resize them again or even worse have them already in loaded ammo and that ammo no longer fits the chamber.

I feel that too much tin is a bad thing. I've seen bullets cause leading with too much tin, bad leading. You don't really need a lot of tin to harvest the benefits of it.

There is much more to this then just melting alloy, casting, lubing/sizing, and shooting them.

[rjathon]

Thank you very much. My questions are answered decisively!