Oversized cast boolits

[dtknowles]

I don't understand how the alloy or the hardness has anything to do with it. the mold is what the mold is if it's 358 it should cast bullets at 358 can they possibly grow after I open the mold

You measured the mold while it was cold. It gets bigger when it is hot. Lead and aluminum don't have the same coefficient of thermal expansion and each alloy has a different casting temperature and coefficient of thermal expansion.

They don't get bigger after you open the mold, they shrink but some more than others.

Tim

[waksupi]

You may need to tap the alignment pins in a bit.

[Conditor22]

Pictures would be helpful

[Dusty Bannister]

Yes, with the bullets from a variety of angles in one photo and the mold as it is held when filling from the pot.

[Microgun]

Thanks for all the responses. I will check for a gap between the two halves. I'm almost positive that I poured a bunch of times when the sprew plate was not 100% under the holding Bolt

[Microgun]

I believe there's also an issue with the swaging die it was very hard going through that die. I thought I was going to break the handle off of my rock chucker press. in fact I ran a few 9 mm heads through the 357 swaging die and it wiped the lube grooves completely off on the 9 mm, it should not have hardly touched those

[Microgun]

Okay so I took the mold apart I cleaned it up I found two very small pieces of lead in between the two halves but beyond that there is almost .003 of an inch Gap in between the two halves of the mold. Is there any way to remove the alignment pins from the mold so I can Mill each side down enough to mate them correctly

[Microgun]

So of the factory available molds like Lee, Lyman, RCBS, Seaco. without going to a custom mold what would be the best quality in order from best to worst

[Dusty Bannister]

Okay so I took the mold apart I cleaned it up I found two very small pieces of lead in between the two halves.

This can create a gap that would produce oversized or out of round cast bullets/boolits.

There is almost .003 of an inch Gap in between the two halves of the mold.

Are the two mold halves held apart by one or both of the alignment pins extending out too far from the mold block? Generally, these aluminum molds do best when heat cycled several times before putting them into production casting bullets. If the pins are actually holding the blocks apart, sometimes warming the mold blocks and then with the mold half on a flat piece of wood, tap the pin with a brass hammer until the blocks can fully close. Milling the mold half is probably not needed.

Is there any way to remove the alignment pins from the mold so I can Mill each side down enough to mate them correctly

Why be concerned about that until you prove that the blocks are not correctly fit when fully closed?

[Mitch]

Is the mold warped as in gap in the middle and touching on the ends?

[popper]

Make sure the (female) pins have no junk on them. Mould lube will coat them. As it's a lee mould, lightly tap the pin in. Tap, measure, repeat as needed. Also check around the pins for Al flash. Use GOOD straight edge to verify mould face flatness. You don't mill the face. Place on flat plate and oily valve compound. Same with sprue plate if needed. IHHO, 3 thous. isn't the problem, you are talking 10. I use Accurate but NOE is good, cost is reasonable but get a 4 hole mould. I only use 2 hole for rifle - more consistent results. And just as fast as my (long gone) 30/30 6x Lee. If you bought from Lee (midway, etc) and the mould is bad, send it back!
For pure Pb, pot temp should by 650F or so. Hotter takes awhile to cool but also heats up the mould more and bullets are slightly bigger - holes expand.
If using Lee sizer, verify the sized bullet OD. Pure comes out much smaller, no 'spring back'. Out of 7, 2 are as marked.

[Mk42gunner]

Check the area around the alignment pins for swelling. I have one of the group buy molds from years ago did almost exactly what yours is doing. It about drove me nuts figuring out what the problem was. I guess the pilot hole for the alignment pins was either unlubed or undersized when they were driven in.

I trimmed the area around mine with a knife (not very neatly, but by then I was ready to throw it in the trash) and reset the pins, good mold ever since.

Robert

[Conditor22]

Okay so I took the mold apart I cleaned it up I found two very small pieces of lead in between the two halves but beyond that there is almost .003 of an inch Gap in between the two halves of the mold. Is there any way to remove the alignment pins from the mold so I can Mill each side down enough to mate them correctly

Again a picture of the gap would be very helpful

the alignment pins can be tapped in or out as needed. I have been known to put the mold in a vise (no handles) and clamp it together often moving long w=allignment pins a little.

IF the mold (not just the alignment pins) are toughing on both ends and there is a gap in the middle -- unfortunately somehow the mold got warped, I know of no simple fix.

sanding the face until the warp is gone will give you different sized/out of round cavities, the center ones will be bigger and rounder while the ones on the ends smaller and more oval in shape.

yes you could cast some hard boolits out of the middle cavities and polish the outer cavities until they are the same size again ---- a lot of work.