Defect in bullet base

[HP9MM]

I am having a defect in the bullet base a number of times. I have adjusted the time I cut the sprue, the melting temp and paying more attention to pouring the lead and I can't seem to find a cure. Your help and advice is appreciated.

[HP9MM]

The defect is at the edge of the base not in the sprue cut.

[megasupermagnum]

Your sprue plate is too cold. That defect is cold flow, and your base edge is not as sharp as it can be. The cure is to dump a little more lead on the sprue plate when pouring.

[bmortell]

things that look like that are usually from too cold. the corner of the base looks rounded a bit which also means the same thing. normally what boolits look like before everything is warmed up and in the steady casting state.

[wv109323]

Either your mold, alloy or sprue plate is too cold.
The base is also rounded and a void is present.
I would preheat my mold and sprue plate, raise my alloy temp to 725.
Get the molten lead into the mold quickly. Try casting fast so that you get frosted boolits thenslow up.

[wv109323]

I forgot to mention a more generous sprue.

[HP9MM]

I will try what you are suggesting and report back.
Thanks for your time.

[bedbugbilly]

I'm a "dipper" so can't speak to the bottom pour pots. One thing I learned many years ago was not to be afraid to make a good puddle on the sprue plate - it helps keep the sprue plate hot and better flow to the base for fill out on a base pour mold. Having excess lead on the sprue plate doesn't hurt anything - it really doesn't
t make it any harder to cut the sprue as you are still just cutting the area of the sprue hole. I cu my sprue and either let them fall back into the pot or drop them off to the side on a piece of metal - let them accumulate and then take a break and carefully add them back to the pot.

You're doing good so don't get discouraged - every issue is a learning opportunity that will help you down the road with other molds and bullet configurations.

[lar45]

It looks to me like you are getting a cold drop that is solidifying instead of melting into the bullet.
Try setting an ingot mold under your bottom pour spout, then just before you fill the mold, bump the pour handle for a second to get rid of the cold dribble that is hanging on the end of the spout. Then pour as usual with a large sprue puddle and a warm mold and sprue plate.
Also preheat your molds if you are not doing that already.

GoodSteel showed me that one.

[Thin Man]

It might also be worth while to examine your sprue plate and mold blocks. Does the sprue cutter hold flush with the top of the mold blocks when closed (cannot see light between them when closed)? Is it completely flat front to back or does it arch up and away from the hinge screw? Is there any lingering lead debris built up on the bottom of the sprue plate or top of the mold blocks? A close order examination may reveal an issue in addition to the previously mentioned suggestions about increasing your alloy temperature. Good luck with your search.

[mdi]

Is the defect at the same place, same size every cast? From what I see I agree with the fellers above, cool/cold sprue plate causing wrinkles in the base...

[HP9MM]

I have pouring bigger sprues and quality of bullets is now almost 100%.
Thanks!

[gwpercle]

Also be aware ...when you first start casting the sprue plate will be tight but sometimes as you cast and everything starts getting hot the plate may loosen...metal expands when heated...when you notice the plate getting loose , stop and tighten it back down...this will keep the boolit base flat and eliminate that little nub where the sprue plate rises when loose and it cuts over instead of dead level.
Practice makes perfect...keep on doing it !
Gary

[fredj338]

That defect looks waaay to uniform. Is ti the same every time? Check the bottom of your sprue plate. You may have a chunk of lead stuck there. Good bases are hot mold & alloy. Break the plate only after the spru is hard & not too long after.