bullet measurements

[Kevin Stenberg]

Is there somewhere I can go to get the specific measurements bullets are supposed to cast at. So I can look at the differences without having to purchase molds with dimensions wrong for the needs.

 

[gman]

As an example Accurate and NOE molds list the bullet drawing showing measurements. The alloy you use will have a bearing on that. With the Accurate molds you pretty much tell Tom what size you want.

 

[Brad]

Lyman and Lee, doesn't matter anyway. You get what you get specs be damned.

NOE and Accurate are good at giving dimensioned drawing so you can have an idea of what you will get. All of this is, of course, dependent upon alloy choice.

 

[fiver]

Tom will work with your alloy choice.
NOE cuts them to pour about .002 over with WW alloy.

fun ain't it

you can manipulate their molds through heat and by adding lead/tin/antimony to your alloy.
this actually customizes the fitment even further.
the 165-A mold I got from Tom with the right alloy and mold temp will pour exactly to 310 on the front band and 3105 on the rear and 301 on the nose
if I scuff the front drive band in the 310 size die the boolit is a reject.

 

[Ian]

Yup, Accurate and NOE. Fiver's right about NOE, and that includes the nose so figure on dumbing down your alloy and using a cool alloy and mould to cast small if you have a tight bore. Accurate will make exactly what you ask for, IF you know what your alloy is or at least have some experience fine-tuning various scraps to work with a mould spec'd for a certain alloy. As an example, I usually ask Tom to make mine to the normal +.002", -.000" spec using straight WW alloy. If I use straight clip-on WW, they usually cast about half a thousandth large. If I add 1% tin, they cast about .001" over, which is right in the middle of the tolerance. If I use 50/50 WW/soft scrap, they cast exactly on. If I use 50/50 clip-on/pure, they cast about half a thousandth under unless I run the alloy up near 750 and the mould on the cooler side, then I'm back to spot-on spec.

 

[fiver]

that's close to what I see with Tom's molds too.
I'm generally about 715-725 and at a light galvanizing on just the center of the boolit as far as mold temp. [about 400-f]
low tin and low antimony barely adjusted till I see the right numbers then run the pot down [bout 30 lbs]

 

[Kevin Stenberg]

Sorry I should have said in my opening that I know about Tom and NOE. I was wondering about over the counter molds.
Ian I was not aware of your posted alloy's and size variation. I will keep that in mined with my next order with Tom.

 

[Ian]

Kevin, check out Lyman's cast bullet handbook #3 for all the info on various alloys and how the various constituents affect final cast diameter and toughness. This goes for any mould. What isn't discussed in that book is how mould temperature, alloy temperature, and age also affect bullet diameter. I haven't pegged the exact metal that causes it, but sometimes bullets will grow significantly as they age harden. Pretty sure it's antimony that does most of the growing as it precipitation-hardens it, but sometimes it is dramatic, like nearly a thousandth of an inch in a month, so I think there's a catalyst, perhaps calcium or zinc that sometimes makes bullets grow more than other times as they age.

 

[Josh]

Kevin, check out Lyman's cast bullet handbook #3 for all the info on various alloys and how the various constituents affect final cast diameter and toughness. This goes for any mould. What isn't discussed in that book is how mould temperature, alloy temperature, and age also affect bullet diameter. I haven't pegged the exact metal that causes it, but sometimes bullets will grow significantly as they age harden. Pretty sure it's antimony that does most of the growing as it precipitation-hardens it, but sometimes it is dramatic, like nearly a thousandth of an inch in a month, so I think there's a catalyst, perhaps calcium or zinc that sometimes makes bullets grow more than other times as they age.

I do believe it is Zinc, I had a batch of lead given to me (racecar weight) and when I melted it down it has the cottage cheese look. I skimmed and skimmed and cleaned it, instead of tossing the batch I cast up plinker 312-155-2R's for the 300 Blk. Sized and lubed to .310 and then loaded. Well 2 months later I take the ammo to the range, most wont chamber, the neck diameter grew by 0.0015". After pulling them down and then measuring the previous cast bullets, most grew by 0.001" so they all needed a 2nd trip through the sizer.

 

[fiver]

copper and calcium can do it too.