Problem with Lyman 429421

[Lonegun1894]

I picked up a mold recently, and while used, it seems to be in pretty good condition. Anyway, cleaned it up, got my leadpot going, and started casting. Here is where things went odd. Now, I have seen bullets stick in molds before, so that was nothing new, but this one seems to have a nasty habit of cracking the very front band of the bullet. It is a slight crack like the driving band of the bullet is sticking in the mold and attempting to break off of the rest of the bullet itself right where the band connects to the nose. I let the mold cool, cleaned it again, inspected it again without finding any defects, scratched my head for a while, and tried again, with the same results. I ran a few q-tips over the edges thinking maybe there was a sharp protrusion that I couldn't see, and was unable to find anything. I then thought maybe I messed up my alloy somehow, and tried several other molds and was unable to duplicate any kind of problem with the others, so am sure there is something with this mold that I am missing. How would you all suggest that I go about fixing this issue? I don't want to give up and sell this, and if need be, will just cast with the one cavity that isn't doing this because that one shoots great in my Ruger SBH. Speaking of which, it doesn't do this all the time, just 1 out of 3-4 bullets cast in the front cavity. So very frequently, but not everytime, which is another reason I can't seem to figure this out. Any thoughts or advice? Thanks everyone!

[gunarea]

Hey Lonegun 1894
Man made objects are always subject to flaw. You should give both cavities a good polishing or a light beageling. Lately I have simply polished new moulds matter of factly.
Roy

[Yodogsandman]

Try waiting a few seconds after cutting the sprue and before opening your mold. You could be opening the mold just before the lead has "set". You might have to slow your cadence a bit allowing the mold to cool more. Maybe just pouring the other cavity first would help.

[LUCKYDAWG13]

I have a Lyman mold that did the same thing i had what looked to be a small piece of tin that was stuck to the mold just under the driving band
i had to melt it off and use a small pick to get it off i think the cause was using range lead and adding pewter to the mix

[chsparkman]

Try waiting a few seconds after cutting the sprue and before opening your mold. You could be opening the mold just before the lead has "set". You might have to slow your cadence a bit allowing the mold to cool more. Maybe just pouring the other cavity first would help.

This was my problem while casting with the same mould last summer. Slowing down fixed it.

[Guesser]

I had that with a 454424, slowing cadence helped.

[Mal Paso]

The top band is 90 degrees and if the bullet isn't completely set, friction when opening the mold can do that.

More mold time or running a bit cooler. I used to run 2, 4 cavity 429421 molds at the same time and that cuts down a lot of defects. Iron holds heat. I've since lapped one of the molds larger and it stopped pulling on that front band. I might still be running those 2 Lyman molds if they had cast large enough to fit my guns.

[Lonegun1894]

Sounds like I'll try cleaning again and slow down since those are the two easiest suggestions, you know, simple solutions first, right? Thanks y'all. I was thinking beagling maybe needed, but never thought of slowing down. Shows how much I know. Thanks y'all!

[Iron Mike Golf]

I have a 452460 that does that. If I open the mold by tapping the handle hinge bolt, the bands don't break.