Alloy weight question

[6.5X284ever]

I have been spending alot of time on the Accurate Mold website, most of the designs that I find most interesting are just a little heavier than I would like, but they are also rated using COWW. At least initially I will be using hardball alloy. If I am understanding correctly, I might be 8% less than COWW ? So a boolit advertised at 265 might drop as light as 243 using the harder alloy ? I do realize that advertised weights are not always accurate.

[kevin c]

If you go to the FAQ, or to the actual mold specifications form when ordering, you can specify the alloy you will be using and Tom will actually alter the machining of your mold so it will drop pretty much dead on for weight. You can even specify the +/- tolerances to suit how it contacts your sizing die if you want to. Premium service, I should say.

[6.5X284ever]

I have read thru the FAQ, was under the impression that the alloy choice was more related to shrinkage/diameter, as the dimensions are already set unless I specify changes ?

[kevin c]

Maybe I read into it differently from what you got from the same statements, but I believe the cavity volume determines the weight of alloy the cast will have, and that Tom can alter that volume to maintain the weight for different alloys just as he can alter the shape to maintain the final diameter as different alloys shrink.

I guess contacting Tom would give the definitive answer, unless somebody who has worked with Tom on the molds he made for him already knows for sure and can enlighten us both.

Or maybe my own experience sheds some light on the original concern. I was starting out, ordered molds and entered hardball as the alloy but ended up using basically COWW +tin (95-3-2). As cast, iirc, the bullets dropped a little heavy, but I’m pretty sure it wasn’t an 8% difference, more like 1-2 grains for a 147 grain 9mm slug. Part of that is maybe that an alloy has some of the characteristics of a solution, where metals are considered dissolved into each other and end up occupying less physical volume than when separate. Just what density each specific alloy has is something Tom would know and could (would?) adjust for.

[6.5X284ever]

I emailed Tom once, but I am just starting out and I don't want to bother him too much until I have a better idea of what I'm doing. I'm sure he's busy.

[kevin c]

I gotta think that somebody as experienced as Tom, who machines custom molds using sophisticated design software and cnc machine tools, knows what’s possible to make (“your design will cast between “x” and “y” grains, depending on alloy, not “z” as you hoped, so maybe we should change the meplat/ogive/shank/# of lube grooves or whatever”), so that his library of designs already has variants to accommodate what alloy is specified.

There’s also the consideration that a few grains difference from nominal isn’t critical in most uses, so long as the weight is consistent in that difference. Powder charge can be altered, for instance, to maintain the same energy on target, if the application demands it. Sometimes the difference makes no practical difference at all (paper punching and plinking with pistols comes to mind).

[racepres]

There’s also the consideration that a few grains difference from nominal isn’t critical in most uses, so long as the weight is consistent in that difference. Powder charge can be altered, for instance, to maintain the same energy on target, if the application demands it. Sometimes the difference makes no practical difference at all (paper punching and plinking with pistols comes to mind).

This^^^, as I would Not be the guy to make a New Cherry, for every customer...and if I did...No one would buy it due to Expense.
But maybe cherries are Cheap??

[JonB_in_Glencoe]

Do you know exactly what you want? I ask, because you mention you are new to this.
If not, start a conversation with us, mentioning caliber and gun and your goals/application.
I suggest starting a new thread with an appropriate title to attract the most members to the conversation.
.
As to your OP, I'm not sure 8% is the difference, but even if it is, I wouldn't worry about that ...I'd worry more about what alloy would be best for your application, as well as getting a good boolit design to fit your gun's throat.

[6.5X284ever]

I'll simplify my original question a little. If a certain .43 bullet drops at 265 with COWW, what's you BEST GUESS at what it will drop using 92-6-2 ?

[kevin c]

I’m not a mold maker, but maybe a given cherry, designed with a certain amount diameter shrinkage in mind, can bore a cavity to slight different depths, giving different weights?

And just how are inletted features like steps and lube grooves done, anyway? I always thought the blocks were machined while clamped together so you can’t just bore them out from the base opening. Some sort of cutter inserted into the cavity with its own spindle offset and rotating around the center axis?

Sorry to thread drift.

If you can wait a day or so, I have both hardball alloy and one similar to COWW with added tin (95-3-2), and can cast up the same bullet in each alloy for comparison.

[243winxb]

Redding website. - Quote:
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 .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 .

[243winxb]

My test using different alloys.

[fredj338]

I have several Accurate molds & the final weight will not be exact. COWW is what I order but COWW can be all over on composition, then casting temps change final size a bit.
If you find a mold design you like but want it lighter, ask Tom to make that weight.

[fredj338]

This^^^, as I would Not be the guy to make a New Cherry, for every customer...and if I did...No one would buy it due to Expense.
But maybe cherries are Cheap??

Accurate are CNC machined, why there are no true round nose designs. Also why Tom can make small changes to any mold & give you what you want. He is great to work with & the quality is top notch. Just dont expect your bullet to hit weight with anything but known alloy like Lyman #2 or Lino.

[Bazoo]

Win243 already quoted it, according to Saeco's catalog, wheel weight alloy will be 3% heavier than Taracorp Magnum alloy. Taracorp Magnum is identical to hardball.

[JonB_in_Glencoe]

I'll simplify my original question a little. If a certain .43 bullet drops at 265 with COWW, what's you BEST GUESS at what it will drop using 92-6-2 ?

First, it doesn't matter.
Second, if Redding says 3% lighter, then I'd go with that, which is about 257gr. Does it matter? Nope.

[6.5X284ever]

In this case, I think you're right, probably doesn't matter. Was initially planning on something in the 240 range, but looks like I'll end up a little heavier. Shouldn't be a big deal. I'm certain that I would be fine with what I already have, but where's the fun in that ? Tinkering with this stuff and thinking about it is half the fun !

[Delkal]

Like others have said.....it doesn't matter. And when loading use loads for the published weight the bullet is supposed to cast and don't try and find data for for 232 or 248 grain bullets.

[Rickf1985]

Lead casting has gotten FAR to involved!! People want to make their own alloys and they expect them to be perfect to the last 1/2% every time. Do you realize that all of the alloy calculators out there that I have seen use 8BHN for their pure lead composition. There is usually a note somewhere mentioning that pure is an alloy of lead and antimony. SO, When you run those calculators and if you are using real pure lead the ending figures are going to be off. WAY off if you are mixing up 10 or 20 lbs. 100 years ago they made bullets without all of this math and without the starting alloys we have now. 70-80 years ago we made perfect bullets that worked just as well as all these fancy alloys without the math and expense put into it now. New is not always better.

[racepres]

Lead casting has gotten FAR to involved!! People want to make their own alloys and they expect them to be perfect to the last 1/2% every time. Do you realize that all of the alloy calculators out there that I have seen use 8BHN for their pure lead composition. There is usually a note somewhere mentioning that pure is an alloy of lead and antimony. SO, When you run those calculators and if you are using real pure lead the ending figures are going to be off. WAY off if you are mixing up 10 or 20 lbs. 100 years ago they made bullets without all of this math and without the starting alloys we have now. 70-80 years ago we made perfect bullets that worked just as well as all these fancy alloys without the math and expense put into it now. New is not always better.

Aint that the truth!!!!