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I have a new MP mold that I cleaned, cycled and have cast with 3 different times and I only get a few acceptable bullets. The bullets hang up, tear the base and will deform the hp's, I have cleaned several times with soap, water and toothbrush and have tried casting hot. I was wandering if I should Lee-ment the cavities? Thanks in advance for your advice.
I’d take a popsicle stick of bamboo skewer and run it around the edge of the cavities to remove burrs that are probably causing it to hang up. Then go from there.
What is the composition of your melt, and at what temperature are you casting? It's likely that neither of these things is the whole cause of your difficulties, but they might contribute to them.
I know that this is laziness on my part, but I don't know how many times I've fixed bad casting results with some extra tin and (sometimes) a little more heat.
I have a similar problem with my 4 cavity mold, They are mostly all keepers but dang things refuse to drop out of the mold, gotta beat the snot out of it to get them to release, Using a wood hammer of course! The non hp versions drop just fine. I will watch and learn from this thread! Brass mp hp molds are new to me.
The heat has to be just right to get release from the pins. Polishing the pins helps, too. I usually have a small wooden mallet that I tap on the hinge pin as I open the mold. Not hard at all, just enough of shock or vibration to help the boolits release from the cavities. If the mold is a little too hot or cool, getting the boolits out of the mold or off the pins is much more difficult.
Some things you might try if you haven’t already. Run it with the solid pins to see if it is the cavities or the pins. Make sure the pins will slide freely on their own weight when you tip the mold. Don’t have the guide pins for the hp pins too snug, back them off 1/8 of a turn from snug. Try waiting a little longer after the sprue frosts to open the mold.
Is it brass ?
I hated that gosh darn dog kid . It wouldn't cast , lopsided pours , too hot , too cold , too fast , too slow , too clean? It took me a dozen heat cycles and 19 sessions to get keepers . Then it was like someone flipped a switch and bam 80% out of 20# pot . I was pouring the 462-420 so at 900+ gr per pour it doesn't take long to pour 15# of metal . Also this was the PB/HB version .
I am using wheel weight ingots with nothing added, I use this mixture all the time with my other mp brass molds as well as noe aluminum molds with no issues at all. I use a Lee 20 lb pot and keep the setting on number 6 for every mold I use, I have never had this issue with any other mold except a Lee 2 cavity that I lee mented and fixed the problem. I will switch to the solid nose pins and see if the bullets will release but I am pretty sure the pins release just fine. I am leaning toward a burr on the cavities, By the way MP hollow point molds are my favorite to cast with. The 45 and 44 caliber hp bullets I have cast from mp is the best.
With boolits that heavy, I have to have a real high/fast flow rate out of the nozzle for them to come out right.
I run my pot pretty hot, and to keep from getting much of a shrink hole, I have a piece of 2 x 4 right in front of the pot.
As bring the full mold away from under the pot, I let it have just a little bit of a tap/drop/bounce on the wood block.
It seems to settle the alloy into the mold better too for a good fill out.
Sounds more like an off center mould. Measure the cavities from the faces if the mould blocks they should be with in a couple 3 thousandths of each other. Much more than that and you have a C shaped cavity that mechanically locks the bullets into the cavity, always the same side too
I appreciate the help.