Base not filling out

[hatchetjack]

Lyman 4 cav , bullet base next to spruce plate bolt, not filling out. All the others OK.
Help- what is the problem ? I have tried filling it frst and last still have the problem.

[country gent]

It may be a venting problem with the last cavity. I would try cleaning the vent lines with a scribe ice pick or awl. Just lightly pull thu the vent lines removing any build ups. Another trick is to stone the top edge at 45* and .005-.010 deep making a small vee under the sprue plate to help it vent off air and gases. I do this with a very fine Arkansas stone or a piece of 600 grit sand paper glued to a small piece of flat stock. Work slow and carefully when doing this.
With the other 3 cavities filling out I don't think its a temp or alloy issue.

[Yodogsandman]

First, try loosening the sprue plate a hair.

[Mr Peabody]

First, try loosening the sprue plate a hair.

then try changing the order in which you fill the cavities

[hatchetjack]

I cleaned out the vent lines, that helped. Then I kept loosening the screw until the base filled out. The lock washer was just touching by then. But I stared to get all 4 bullets filled out. Thanks for the help. You would think the base of the bullets would not be flat BUT they are !!!!!!!

[waco]

I had the same problem years ago on a Lyman 4 cavity. It was a heat issue. Get the mold HOT. I preheat on a hot plate now. Problem solved.

[country gent]

You might try a light bevel down each top edge of the blocks very light. .005X 45*. when you see a sliver line even along it, it should be enough. This forms a vent line right under the sprue plate.

[Strtspdlx]

I would listen to Waco. If it's near the bolt that's probably the fastest to cool. Lyman 4 cavity molds I usually get so hot they throw very frosted bullets then slow down my pace until the frosting just goes away then try to maintain that temp or bullet apoearance in the mold. How quickly is the sprue solidifying?