Casting undersized .40 cal. in Saeco mold

[Joe's]

Some time ago I bought a Saeco (Redding) .40 cal. mold from Midway. Finally got around to casting with it. It only produces bullets that are mostly .3985 and .399. very few come out at .3995 and hardly any at all are .40.
As you can guess they don't size very well in the Saeco (Redding) sizer and punch dies, .401.

Does anyone else have this problem or is it just me or the lead?

Thanks for your help,
Joe's

 

[Curator]

Joe,

Try casting hotter (around 750 degrees F), both mould and alloy. Make sure you have at least 1/2% tin added to get good fill-out. If after that you are still getting undersize bullets send the mould back to where you bought it.

 

[243winxb]

Have 3 older Saeco moulds, all cast on the large side. Add antimony to your alloy. Antimony is the best way to increase diameter. Linotype works well adding both tin & antimony.

Bullet Sizes and 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).

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.


http://www.redding-reloading.com/pag...etweights.html

 

[Walkalong]

Yep, change alloy to change as cast diameters.

 

[Joe's]

Thanks guys for the responses. However your answers are confusing.

The mix I have been using has about 1% tin, 3% antimony, and 96% pure lead from electric cables.In the response from Curator he suggests casting at a higher temperature. I don't have a lead thermometer. Any hotter and they come out gold colored and then finally blue. So I then I have to back the heat off and basically start over. Then in 243winxb"s post, in the statement from Redding, they suggest using to high of a temperature will cause more shrinkage as the bullet cools.
I think I will try Reddings answer and cast at a lower temp. If that doesn't work it's going back to Midway. IIRC it cost about 129.00 give or take.
I also think I'll try adding a little more antimony. About 6% total.

Thanks Again,
Joe's

 

[243winxb]

Bullets become frosted if the alloy and/or mould become to hot. A frosted bullet will be slightly smaller than a shiney bullet, but not by much.