casting under size, or bullet shrinkage?

[Will52100]

I'm pretty well set with my moulds and alloys, but I've got a friend that is just getting into casting and is having trouble with bullet shrinkage.  He's sizing .452 and a within a week there around .450-.449.  He's using pure wheel weight.  I don't have a shrinkage problem, I'm using the same # mould and getting .453-.454.  Only differance is that I'm pan lubing and sizing up to a week latter and my alloy is about 4 parts WW to 1 part soft lead.  Any ideas?

Thanks

[Lloyd Smale]

I like to let my bullets cool at least overnight. If you size them when there still warm your bound to be some shrinkage.

[Will52100]

Thanks, I think there may also be too much release agent in the mould cavities, we were having trouble getting the bullets to drop without banging on the mould.  The mould cavities are .456.

[gutshot_again]

I'd check the sizing die and see if it really is .452 or more likely sizing them to .450.  I'd also check the mike's used to measure the bullets (and have one guy do both measuring wth the same mike).  I'd bet it's one or the other.

I'd also clean the release agent out and if the bullets stick, do a little polishing with a bullet cast in that mould.  Chore boy or maybe even tooth paste should do the trick.

[Will52100]

I checked both bullets with two differant mikes, some of the bullets were just barrely sizing at .452 when they should have been dropping at .454.  Normaly I size at .454 and just barely shave lead, very little contact.  While the sizer could be undersize the bullets are still casting undersize.  The more I think about it the more I think it's just a build up of release agent.

Thanks

[gutshot_again]

I would not doubt it is a build up.  I purchased a 358009 that the previous owner used the release agent.  Bullets cast at .356 and I was bummed.  After cleaning down to the bare metal, they started casting at .359 - .360.

I have had moulds that would not release the bullets either.  By lapping the cavity(ies) with toothpaste on a bullet cast from that mould, the problem goes away.  BTW, when I said chore boy, I meant to say Comet or Flitz's bartender's friend (or some name like that).  I would not use lapping compound unless I know for sure the mould was worthless and I had nothing to lose.

[Will52100]

I knew what you were talking about, I've done that to most of my moulds, except I used commet cleaner and water, I did use JB bore compound on one troublesome mould.  Other than a little minor tune up I've had very little trouble with lee moulds, even there crapy 17$ two cavities, though I've got one in .458 that I can't get to fill out for nothing.

[Lloyd Smale]

i wont use mold release or anything that coats a block. its taking up room that lead should be.

[Graybeard]

I will smoke one at times to help the bullets fill out but long ago learned that mould release stuff causes more problems than it solves.

[Will52100]

Think I got it fixed, used the commet cleaner and drill trick, took most of the release agent out except for low spots here and there.  It cast .454 as droped, I'll see over the next few days if the alloy shrinks any more than that.  The bullets fall out of the mould a lot better now than it used to.  I had to get pretty agressive with the drill and commet, I wouldn't try any thing harsher though.  I did use the mould release from rapine on the sprue plate and the top of the mould, but I tend to agree that non should go inside unless you want smaller bullets.