IllinoisCoyoteHunter
12-31-2014, 04:25 PM
I found this calculator really helped me dial in my adjustable core mold is short order. All you need to know is the diameter of your core and the weight of core you want to produce. Be sure to set the "Precision" to 5. It displays the weight in pounds so you have to have another calculator to go from grains to pounds...but they are all over the net. Punch in different lengths, in inches, until you get the right weight (in pounds) On my 6 cavity mold I adjusted 3 cavities in .010" increments larger than what the calculator said and 2 shorter, in the same .010" increments.
Example: I was looking for a 182 grain core. My core mold is .335" in diameter.
Units = Inches
Precision = 5
Material = Lead
Density = .4100 lb/in3 - this automatically pops up when you choose lead as your material
Shape = Cylinder
Then click the button "Add Shape"
Diameter = .335
Height = This is where trial and error comes in. Punch in different heights (lengths) until your desired weight is achieved. In this case 182 grains is .02600 pounds. To get that weight in pounds, the length of the core needs to be .720" long. This is a great starting point.
So I would adjust my cavities to the following lengths - .700", .710", .720", .730", .740", .750"
In my case, I found that .740" was right on the money and filled the jacket perfectly. Of course everyones alloy will be a little different. Then I backed out the other core cavities that were too small and placed the .740" core in them. I them closed the mold and screwed the adjustment until it stopped firmly against the base of the core. I could tell that the top of the core was just touching the sprue plate. I then tightened the set screw. I then put one core aside and put it in a baggie so it could be used again to reset the cavities for that particular bullet. Weight varied less than 1 grain between the 6 cavities. For my pistol shooting this is acceptable. This can also be used even it you are using a squirt die. It will get you close with less trial and error.
Hope this helps!
Here is a link to the calculator: http://www.custompartnet.com/quick-tool/weight-calculator
Example: I was looking for a 182 grain core. My core mold is .335" in diameter.
Units = Inches
Precision = 5
Material = Lead
Density = .4100 lb/in3 - this automatically pops up when you choose lead as your material
Shape = Cylinder
Then click the button "Add Shape"
Diameter = .335
Height = This is where trial and error comes in. Punch in different heights (lengths) until your desired weight is achieved. In this case 182 grains is .02600 pounds. To get that weight in pounds, the length of the core needs to be .720" long. This is a great starting point.
So I would adjust my cavities to the following lengths - .700", .710", .720", .730", .740", .750"
In my case, I found that .740" was right on the money and filled the jacket perfectly. Of course everyones alloy will be a little different. Then I backed out the other core cavities that were too small and placed the .740" core in them. I them closed the mold and screwed the adjustment until it stopped firmly against the base of the core. I could tell that the top of the core was just touching the sprue plate. I then tightened the set screw. I then put one core aside and put it in a baggie so it could be used again to reset the cavities for that particular bullet. Weight varied less than 1 grain between the 6 cavities. For my pistol shooting this is acceptable. This can also be used even it you are using a squirt die. It will get you close with less trial and error.
Hope this helps!
Here is a link to the calculator: http://www.custompartnet.com/quick-tool/weight-calculator