Casting alloys and dropped bullet diameter?

[Naphtali]

I have not cast lead-tin ONLY bullets. Do bullets having only tin as their alloying metal drop with slightly larger diameter, as do bullets made from lead-tin-antimony-(other) alloys?

[Bret4207]

My understanding is it's antimony that causes larger boolits to be produced.

[Shiloh]

+1 to Bret.

It is the antimony that causes the boolits to remain larger. Has something to do with setting up before it can shrink in the cavities.

Tin is for proper fillout.

SHiloh

[RobS]

Yep the bullet will be smaller in diameter that is only tin/lead than lest say WW or Lino.

Here is a link and look at the section "Shrinkage-Bullet Diameter, Inches" Also it's a good bit of general info as well.

http://www.lasc.us/CastBulletNotes.htm

[Naphtali]

Many thanks, guys, for the information.
***
Now for a follow-up question: What is a safe, accepted procedure for casting with antimony (to slightly enlarge dropped O.D.) while keeping bullets soft - and how soft would be "soft?"

I am beginning casting for a muzzleloading rifle. I want the projectile to be harder than pure lead - but not hard. Since I do not yet have the barrel, I am uncertain what is its actual bore-groove diameters. That's why I'm attempting to identify a procedure to give me a few thousandths wiggle room on projectile diameter. I do not want the projectile comparably hardened as are my smokeless powder bullets. I do not want the projectile to be brittle. Probably, the procedure to achieve what I want includes some sort of oven baking. This, again, is something I have not done - air cooling, yes; water dropping, yes; but no baking.

[Cherokee]

I'll leave the real answer to those who shoot muzzleloaders - but - I have always read you should use pure lead.