Casting Hollow-Point Slugs with MP Molds

Over 20 years ago, through the miraculous thing we call the internet, I discovered a small mold company in Slovenia. It was mentioned in the Cast Boolits forum. To a confirmed lead bullet junkie, it was spell-binding. If it worked half as well as it looked, I’d still come out ahead.

These molds were pure art! Made of brass, the cavities were polished bright, and the vent lines looked as though they were designed by the age-old Spirograph. For a mold lover like me, it was almost criminal to use them. But use them I did. My only complaint with these molds — after using them, you will want a second, third, and fourth mold until your bank account is drained dry and it’s beans and bologna for lunch for the next 6 years.

Choking down beans and bologna is easy when you think of the piles of hollow-point bullets you’ll have accrued with these molds. MP Molds makes the easiest mold for casting hollow-point slugs. And for editorial merit, I spell mold just as it is. The other form of mould is the British way of spelling it, and we quit taking orders from them 250 years ago. Lee Precision has the right idea, spelling it M-O-L-D, the way it’s supposed to be spelled.

Mold Warm-Up

When I first started casting bullets, I’d warm my mold up by simply setting a corner of the mold on top of the alloy. As the alloy heated up, so did the mold. When the melted alloy rolled off the mold, I knew it was the same temperature as the alloy. Now I use a hot plate to preheat my molds. Just set the mold on the hot plate at the highest setting and let it heat up.

I start my casting furnace at the same time. When my alloy is melted, the mold is usually pre-heated enough to start dropping perfect bullets. Hollow-point bullets will take longer to preheat because the HP pins need to be heated also to prevent wrinkly bullets.

Let it Flow

Now for the nitty-gritty of filling your mold cavities. It takes a slightly educated hand when using the spout control of the alloy. If you go too slow, your alloy will have a chance to cool, making wrinkly bullets. Too fast, and the alloy will splash and sputter, which leads to partially filled cavities or voids in your bullets. Air pockets are also possible when the alloy comes gushing out of the spout.

A controlled flow will remedy all these maladies. Once the cavity is filled, keep the flow going so the sprue plate cavity is also filled. When your alloy cools, it sometimes sucks in a small amount from the sprue hole. This ensures well-filled-out bullets without voids. Nothing is more satisfying than seeing your alloy flow from pot to mold, taking on a bullet shape of your choosing from the mold cavity, as it transitions from liquid to solid.

Sprue Cut-Off

Once your sprue hardens and changes color, it’s time to hit the sprue plate with your mallet. Your mallet can be a piece of hard wood, rolled rawhide, or a lathe turned small club. Our special projects editor, Roy Huntington, made me a dandy sprue club from hickory for some bullets I cast for him. It’s a pleasure and joy to use this tool when casting. I collect the cutoff sprues in an old bedpan from my wife’s grandmother when she was a nurse.

Tap Out

Once your sprue is cut, turn the mold upside down and give the mold bottom a sharp tap with your sprue mallet. This will loosen the bullets’ grip in their cavity, and they will fall out more easily. Now open the mold halves. Your bullets will be in the cavity, held in by the HP pins. Give the HP pins a light tap to push the bullets out. If they don’t fall from gravity, give the mold a slight tap to knock them from the HP pins.

Easy Peazy

MP Molds are the easiest and fastest way of making hollow-point bullets. They only take a second or two longer than casting solids. MP Molds didn’t invent this mold style. It’s a Cramer-style design that has been very skillfully replicated by owner Mihec Previc. His molds are a pure joy to use, and the service is unbelievable. I’ve ordered molds from him on Monday and received them from Slovenia by Wednesday or Thursday.

So, if you’re crazy for cast hollow-point bullets, check out MP Molds. They are a true bargain!

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