Mold drops undersized bullets

[Dakota954]

Im new to casting and i bought a lyman 2 cavity mold that is supposed to drop .358. I casted some bullets using range lead my uncle gave me (about 15bhn water dropped) i measured them using a caliper and they measured from .356-357. What am i doing wrong? Why are they smaller than the mold?

[Old Caster]

If you are doing something wrong, it is that there isn't enough tin in your mix or your mold and or alloy temperature isn't high enough. Still you may not necessarily be doing any thing wrong though as some molds are made too small. I have a 4 cavity Saeco 148 DEWC .358 mold that makes the bullets .356 and Saeco is almost always the best quality. -- Bill --

[randyrat]

I use a Micrometer. I have 2 calipers and both measure different. I have mark them so I know how they measure.
Your caliper may be off by 1 K...Double check your measurements.

If your measurements are off by a K or so then you can panic.

[462]

If the mould is of new production, many members have posted reports of them casting skinny boolits.

Micrometers are needed to accurately measure boolits.

If, after following the above advise, your boolits are still too skinny, return the mould. I am no longer any company's quality control department.

If the mould is used, and you've followed the above advise and are still getting skinny boolits, search "beagling". It is a method of applying aluminum foil tape to the mould's faces, so that is will cast fat boolits.

[geargnasher]

Lyman specs their moulds for either Linotype or #2 alloy depending on who you believe. In either case, those alloys drop a "fatter" boolit than the alloys we seem to most often use. Lyman has also been having an abnormal amount of QC difficulties and worn-out, undersized cherries and offset mould cavities, too. Your complaint is not uncommon, as I've had a rash of undersized Lyman moulds the last three years or so, and never had a single issue with any of the other brands of production moulds casting below rated nominal diameter with wheel weight alloy.

For this reason, I will never buy another Lyman mould unless it is used and vouched for by a trusted member here.

Gear

[sig2009]

I had a Lee 6 cavity 120gntc that would not drop larger than .356 no matter what combination of alloy I used. Sell it or send it back for replacement!

[runfiverun]

Lyman specs their moulds for either Linotype or #2 alloy depending on who you believe. In either case, those alloys drop a "fatter" boolit than the alloys we seem to most often use. Lyman has also been having an abnormal amount of QC difficulties and worn-out, undersized cherries and offset mould cavities, too. Your complaint is not uncommon, as I've had a rash of undersized Lyman moulds the last three years or so, and never had a single issue with any of the other brands of production moulds casting below rated nominal diameter with wheel weight alloy.

For this reason, I will never buy another Lyman mould unless it is used and vouched for by a trusted member here.

Gear

or untill i start seeing reports of correct/oversized molds.

[dunnrite]

I have a RCBS mould (.40-SWC-200Gr) that casts boolits out of round (.402-.396 or so). I'm going to send it back to RCBS. My Lyman 358311 drops near perfect boolits every time (I did buy it used though). My RCBS .45-SWC-185 throws perfect boolits every time, also. Probably just a bad mould.