Thank you for this advice! I have the same mold and most of my boolits have the flashing. Once I tumble lube them most of the flashing get mashed down or breaks off so it wasn't a huge concern. Just not as purdee as I would have liked.
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I'm new but how about a heat gun set on low with you HP pin sitting by it to keep it at temp
As the alluminium mould heats up quicker than the steel pin we will have a situation where heat will go to the pin as it is colder than the mould . In the example earlier with the coupler where cast steel is used they are working with similar metals for casting and the pin . Expansion and cooling rates would be similar . With lead we need all items to have similar temperatures . Pins would work better when polished and with a small taper .
Pretty boolits
Good info, will definitely remember this thread.
Would a pin made out of brass hold heat better?
I start my HP way hotter than it needs to be. Maybe takes a minute for the first mold full to solidify. Mold cools a little as I work into the rhythm. Never any trouble with sticky boolits that don't want to drop off the pins.
My non HP molds seem to do better starting cooler and letting the casting heat them up and just toss the first few castings back in the pot.
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This is exactly the way I had pour some HP 150 GR 359's today. I started out in the conventional manner of holding mold about 1/4" under nozzle, cast about 20 and threw em back. Held sprue plate directly to nozzle and let off a little for sprue to build a little for each cavity and this got me near perfect bullets! More alloy weight in pot gives better flow too.
In my limited experience:
Run the pot a little hotter than normal
Let the first few bullets linger in the mold to bring it up to heat.
pour hard and fast once you hit temperature.
In a bottom pour keep a good head of lead.
In a Miha mold that is about all I can think of.
With my Lyman mold I twist the pin to free it from the bullet before opening the mold, then use it to remove the actual bullet. I then drop the bullet off the pin and re insert the Pin. End result is the pin is free of hot lead for a very short time.
Hope this is of some use
I keep the brass pretty warm, i hit it with a temp gun quite often. Seems the larger the cast the easier it is for me.
Thanks to a fellow member who recently sold/furnished a two-cavity RCBS 30-180-FN mould with one cavity HP'd, yesterday, I cast my very first HPs. Looks like they came out pretty good for the very first stab. That was a fun session and a valuable learning experience. The projectiles were powder coated, sized and gas checked. I may put one more thin coat of powder coating on them before testing.
Here's a pic of yesterday's handiwork:
https://i.ibb.co/sVCmrmd/IMG-0154.jpg
Bayou52
I have just started casting with a MP 4 cav brass HP mold. I have learned to preheat this mold much hotter than I do for standard molds. And I have payed much more attention to mold temperature as I cast because this mold has a narrow window where it likes to run. I use a three count after the sprue dulls before I cut. Then another three count before I open the mold and dump the boolits. The tricky thing is how long to pause before you pour again. My issue is the mold getting too hot and the edges of the bands and base get rounded on the boolits. They also get frosted.
But i am improving and getting quite a few nice ones.
I keep a hot plate next to the casting furnace to heat moulds that use four pins in hp cavities.
I get them hot and dump the bullets when the sprue has changed color.
I cast using six molds alternating 1 to 6.
after dumping bullets the mould goes on the hot plate till it's turn comes up to fill it,then it sits till its turn to empty it.
Then it sits off the hot plate filled till it's turn comes to empty it, then it goes back on the hot plate.
It gives you quite an arm workout after a while moving all those four cavity molds , filling them and emptying but it makes a big pile of bullets too!
Also the hollow point ends are all filled out.
I also keep another ten pound furnace busy melting lead to keep the main furnace full.
It's easy to empty a twenty pound furnace with twenty five minutes of fast casting using four cavity moulds in 44 and 45 calibers.
Best advice is get a hot plate & USE IT!! Bring molds to 350/375 degrees before staring ta cast. I guaranty the majority of problems will disappear.
CW
I normally turn my lee 4/20 pot up to 8.5 and make sure my mold and pin are hot first. Mold tinning is normal for me at this temp but bullets look great and most weight within 3 grains of each other.
One of my favorite molds. My lead is 96-2-2 that I used to purchase from GT Bullets. The lead has almost doubled in price so I'm looking into mixing my own. But their alloy is perfect for great performing hollow points. My bullets from that mold drop right about 190 grs from their 185 gr mold. Expansion is very impressive and I use those in all my 45s including my carry rounds....Oh No's!!:roll: