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Old 12-19-2009, 10:50 AM
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Why size cast bullets?

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I'm new to this board and have not yet begun to handload. I don't quite understand why I would cast oversize and then size my bullets, rather than just cast bullets of the proper diameter to begin with.


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Old 12-19-2009, 11:44 AM
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Well, for one thing, there are no certainties that the mold you purchase will drop bullets at exactly the correct diameter, even with the alloy known in advance. Manufacturing tolerances, basically. Plus, different alloys will drop at different diameters even with the exact same mold.

Then, different guns will have different tolerances and what works great in one gun might need to be 0.001" larger or smaller in another.

So, long story short, generally the mold will drop a little bigger than most people need, so it is more useful for a wider range of guns / alloys. You have to put lube in the bullets anyway and so using a lubrisizer does both and isn't a wasted step.

Lots of people do shoot unsized bullets and there is nothing wrong with that, if it works out with your mold, alloy, gun, etc.

Hope that helps.

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Old 12-19-2009, 11:53 AM
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Most people do not deliberately cast oversize bullets with the intent of having the chore of sizing them down. Many guns, especially revolvers, have varying cylinder throat diameters. For example the 44 magnum. Cylinder throats commonly run from .429 to .431 diameter. Some older guns may run larger yet. The mold manufactures tend to make their molds on the larger side so it covers these variances. You are fortunate to find one that casts exactly perfect for your gun. Different lead alloys will give slightly different diameters also, as another fly in the ointment. The bullets can then be sized to suit if desired. Generally bullets can be loaded and fired as cast, unsized, using a tumble lube. Oversize bullets are easily swaged down in firing, and some feel the as cast, oversize bullets shoot better than the properly sized ones do. A couple of thousandths oversize is fine. If this works for you, all you need is a bottle of Lee Liquid Alox, a plastic tub and some wax paper to dry the bullets on. It saves buying a sizer and dies. It is an ideal situation for a person with only one or two guns to cast for. Lee makes molds specifically intended to have it's bullets tumble lubed and shot unsized, although just about any mold will suit for this. The main limiting factor on how big the bullets can be, is what will load in the case without bulging and what will chamber. This pretty well works for all kinds of firearms.
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Old 12-19-2009, 07:20 PM
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I have only one mold that casts bullet large enough that I have to size them. The other molds drop bullets about .002 over so all I do is tumble lube them and shoot them. The only time I normally use a sizer is to install gas checks.
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Old 12-19-2009, 08:40 PM
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What I do is use them as cast and find a load that is useful for me, That is more accurate than the most common factory loads for that cartridge. Doing it this way I have never had to size a bullet except for putting on the crimp type gas checks on. I finally went to the cup type basically to avoid sizing.

I may be wrong but it seems that the bullets being unsized were still capable of better accuracy than I am. If I shot a lot of competition I would try it as part of an attempt to get the most accuracy because it may be the difference between losing or winning a match, but otherwise I don't see any reason to size bullets. I have not beaten every factory load in every caliber, but out of 6 calibers and about twice as many molds only one caliber (.32 H&R Mag) would not beat most of the factory loads available to me. Federal 85 gr are so accurate in my Contender barrel that the best I can ever do would be to match it any way.

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Old 12-20-2009, 02:23 AM
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Several of my moulds drop bullets that don't require sizing. Several others probably don't need to be sized but I find sizing is what works for me. A couple of them drop bullets that are enough over-size in my particular firearms that they cause feed problems and do need to be sized.
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Old 12-20-2009, 08:31 AM
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If the mold will drop a bullet the right size, then i don't bother to resize them at all...just tumble lube (or for big bore black powder types, will hand lube). Unfortunately, molds don't always cooperate.

The alloy used has much to do with the size of the bullet that comes out of the mold, with harder alloys casting larger than softer ones. Molds vary in size a bit (if cut with a cheery, will cut a larger size when the cherry is new...smaller sizes as the cherry wears a bit). Older molds were often cut to cast much too large (with the intention of sizing them down, but also seems that being .002" over bore size had a following).

If i had to pick a number to pay attention to, it would be whatever the bore size (or lead size) right ahead of the chamber (or the cylinder mouthes in a revolver). If the load is high enough pressure to bump-up the bullet, it's going to become that size once fired...starting small just lets it bump up uneven. If pressure is too low to slug up the bullet when fired, will usually get leading and poor accuracy. Seems the best choice is to start the bullet out the size it's going to become.
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Old 12-23-2009, 05:24 PM
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Thank you for clearing this up for me. That molds can differ makes sense to me, depending on the tolerances during their manufacturing, but I never would have guessed that different size bullets will come from the same mold depending on the lead used.

It also makes sense that, since they have to be lubed anyway, everything is accomplished in one step. The only process for lubing bullets I was aware of is what I saw in youtue. Tumbling in a bag, or arranging in a tray, pouring in the lube, and pushing the bullets out after the lube dried.

I think I may just stick to buying my bullets for the time being.

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Old 12-31-2009, 09:03 PM
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Originally Posted by Austringer View Post
...I never would have guessed that different size bullets will come from the same mold depending on the lead used. I think I may just stick to buying my bullets for the time being.
I wouldn't have guessed this, either, but have experienced it and it still kind of amazes me.

You can buy your bullets, but that is no guarantee either. Someone else with a web site can produce bullets just as crappy as you can. Conversely, YOU can produce bullets having uniformity as good or poor as anyone else. Without some way of measuring hardness and/or a way to control it, I find there's a bit of guesswork. Currently, I'm relying only on my lead source to be consistent, which is a bit of a roll of the dice.

Note that bullet cost may be the single biggest cost factor in your reloaded ammo cost, depending on what you're reloading. For me, cast bullets purchased commercially cost significantly more than my finished ammo does, so I choose to live with the 'joy' of casting my own for about 1/3 of the cost of buying them (4 cents each vs 10-13 cents each). If you shoot a lot, it makes a big difference, if you don't shoot so much, then not so big a deal.
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Last edited by Bongo Boy; 01-06-2010 at 12:47 PM.
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Old 12-31-2009, 09:33 PM
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Don't have the most current Lyman handbook, but can recommend getting and reading one (even if you rip out the loading data and only read the first chapters).

By their chart:

.45 rifle bullet will range from .4575" (lead) to .4590" (linotype)
.22 Rifle bullet from .2246" (lead) to .2252" (linotype)

Now the odd thing is that even when sized, the harder bullets are predicted to pop out of the sizer a bit larger than the soft bullet...evidnetly, hard lead has a little "spring back" that soft lead doesn't show. So by thyeir numbers, if you ran those .45 rifle bullets through a .457" sizer, the pure lead would end up about .4566" and the linotype about .4574".
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Old 01-01-2010, 05:57 AM
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Lee sells a very inexpensive sizing kit, along with their liquid alox you can size and lube them very inexpensivly. I have been using the Lee sizing kits for about 20 years with great results. The tumble lube bullet mold they sell doesn't need to be sized as there is enough "give" on the outside surface of the bullets that pressures won't spike. they tend to shoot very well also.
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Old 01-02-2010, 02:42 PM
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All the rifle bullets I shoot are actually over groove size by about .001" or .002", and may be larger depending on the rifle's throat. In my experience, cast bullets shoot best unsized almost always. Diameter of the back of the bullet is not the only important diameter: Bore Riding designs also need the nose of the bullet to be land diameter or very slightly larger.

Bullet molds may be advertised as one size, but give you a different diameter. Diameter can be varied somewhat by varying the alloy, casting temperature, and other means.

I use some Lee Liquid Alox, but most of my bullets I put through a conventional Lubricator/sizer. The dies I use on my Lyman lubricator/sizers is almost always the same diameter or larger than the bullet, such that it lubricates, but actually does not size. For my Star lubricators, their throughput is incredible, but they need a bullet a little larger than the die to not leak lube everywhere.
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Old 01-17-2010, 10:02 PM
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Here is another scenario to consider. I use a cast bullet that casts at .380 for my .38-55. I size it and lube at .379 diameter. I also use the same bullet sized .376 or .377 for my .375 Win. Sizing is also supposed to make them perfectly round . I also have a .41 cal mold sized .411 for my .405 Win, sized .410 for my .41 Mag and sized .406 for my .40-65.
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Old 01-22-2010, 05:10 PM
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Bullet Sizes & Weights – How to Vary Them

Different alloy, different bullet diameter as it drops from the mould. http://www.redding-reloading.com/pag...etweights.html
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).

You should be aware that 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.

In order to provide a hard bullet, and due to the availability of high antimony content alloys such as scrap wheel weights and type metal, many casters are using high antimony content alloys. SAECO moulds work well with these high antimony content leads, but you should be aware of the variations they may produce.

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 .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 from 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.
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