How much tin to drop larger boolits?

[ghh3rd]

Any suggestions on how much tin to add to WW in order to 'fatten' them up a bit. I have a 301gr mold that's dropping at .430 and was thinking that a adding little of my 50/50 babbit might drop slightly bigger boolits.

Thanks,


Randy

[lwknight]

I've added up to 10 percent tin and could not tell any difference after 3 percent except that the spru puddle would not pile up and was harder to toss of the plate because it was thin and light.
More tin never made my boolits drop bigger. I do get slightly bigger boolits with 6-7 percent antimony and as a by-product they air drop a lot harder.
IME, less than 2% tin is harder to get a total fill out. 3% should definately square up the bases.

[ghh3rd]

So since Linotype has Antimony, I'd be better off using that?

[lwknight]

Lino cut in half will make "Hardball" (92-2-6 Lead/tin/ant.)
Its a great mix for hard air dropped boolits at about 15 BNH. Water dropped would be a lot harder.
Its generally excepted to cut lino to 1/4 and water drop if you want hard boolits.
I cannot say if pure lino would cast any bigger than 1/2 lino because it has 4% tin.

[454PB]

Yes, pure linotype or harder (monotype, foundry type) casts progressively bigger. For instance, my Lee .452 300 FN GC casts .002" bigger with linotype than it does with WW alloy. With monotype, it's .003" bigger.

[ghh3rd]

So if I had the same results with Lino (+.002 over WW), I suppose 50/50 WW Lino might result in +.001, and a hard boolit.

How were you cooling your boolits - air/water, both types the same way? Do they change much with age?

[454PB]

Yes.

This size difference will vary with design diameter. Using smaller boolits it will have less of an effect.

[ghh3rd]

Regarding my original question - I have learned that I was wrong in thinking that tin will help increase size, but have found out that besides helping lead flow better, tin should help prevent boolits from shrinking after they are cast.