Can Anybody Explain This?

[Silver Jack Hammer]

I think the base of the boolit sticks in half the mould when I open it and the nose of the boolit attaches to the other side of the mould. I believe I'm opening the mould too early and should wait for the alloy to harden a little bit before opening the mould to prevent this.

[Smoke4320]

You are correct. Wait about 2 more seconds to open the mold

[btroj]

When I see that I do two things. Wait a little before opening the mould AND slow down my cadence. Mould temp is likely too hot and cooling it a little will make a big difference.

I use a small fan to cool the mould, makes a big difference. I also watch the base of the bullet after cutting the sprue. If the bullet base looks shiny I am running too fast. That means the bullet isn't hard when I cut the sprue. Dumping those bullets often leads to what you see there.

Look carefully at other bullets from that run. That type of tearing is often pretty subtle but very informative.

[Silver Jack Hammer]

Great. Thanks guys.

[bangerjim]

Agree. Too hot/too soon. Wait a bit B4 dropping.

[RobS]

You can also try and open the mold differently. Sometimes the mold handles as they set on the blocks are off just enough that the mold will sort of bind on the boolit upon opening.

[Ballistics in Scotland]

I see some kind of irregularity, which I can't identify, on the joint line on the nose of the bullet. If it always sticks in the same side of the mould, the edge of the cavith is likely to be very slightly. The original mould which came with my Winchester 1886 is like that, but sharp rap on the mould, over a piece of soft toweling, gets the bullet out.

Exactly the advice given, waiting a moment, will very likely work in a more moderate case. Some would remove a tiny sliver of metal with a modeling knife, although I think rubbing with a smooth piece of metal would be better, expecially with a brass or aluminium mould. Excessive displaced metal could easily be pressed back again on a flat surface.

I've got a large aluminium slab on which I press the bottom of an overheated mould. I always think it removes heat near the nose, where the pressure of a 3/4in depth of lead is working for you, but leaves it hot at the base, where the mould is most difficult to fill properly.