Technique For Casting w/MP Hollow Point Mold

[alamogunr]

Per the title, I've got several MP molds with the hollow point accessories. I've never felt the need for hollow point boolits until now. Because at my age, I'll be passing all my molds to my sons or grandsons one of these days. I decided to pick a mold and cast with all the hollow point inserts. I cast samples with the blank insert, the long pointed. the pyramid type and the cup insert.

Of course, the blank and cup inserts were no problem. The other two presented a need for a different technique. With the limited trial I didn't develop a technique that seemed best to me.

Any suggestions for ejecting the boolits from the mold? Is turning the mold upside down an acceptable way to get them off the hollow point tip? Or is it the only way?

BTW, this is not just one mold. I've got at least a dozen molds with hollow point capability(just in case).

[muskeg13]

I have several MP molds with the HP option, and just received 2 new hollow base molds yesterday. Of all my HP/HB molds, MP HP molds are the easiest to use in producing a large quantity of well-formed boolits. I usually don't need to turn the mold completely upside down, but turn it to one side or the other and using a rawhide mallet, lightly tap the handles or the outside of the mold where the handle attachment screw is located (and I mean lightly tap). Sometimes a pick, small screwdriver or small forceps are helpful in removing a loose boolit hung up in the mechanism.

My main techniques are to cast hot, and before casting make sure the pins move freely and lightly smoke both the cavities and tips of the pins using wood matches. I don't preheat except to rest the mold on the edge of the melting pot as the alloy comes up to temperature. I expect to cast several cycles before the mold comes up to temperature and begins to produce boolits without flaws. Once this occurs, I try to maintain a fast tempo to keep the mold hot. I always cast using at least two, sometimes three, separate molds to give the alloy time to solidify and not overheat the molds. However, sometimes you might need to slow down if lead smears appear on the mold top or sprue plate.

As for casting solids vs HPs, I used the pin combination to cast 2 and 2 last session by alternating pins in the 4 cavity mold. I was surprised to find the HPs a little more tight grouping in a few loads I shot.

MP Molds has a tips/recommended techniques section on their website that may be of interest: https://www.mp-molds.com/tipsntricks/

[fredj338]

I have had good luck smoking the pins. As noted, cast hot to keep the pins hot. A light tap on handle hinge pin with a wood stick helps.

[sureYnot]

I've used all the above. Also, "painting" the pins and their guide rods with a #2 pencil works. All methods seem to work equally well. But I'll be dipped if any of my molds can decide which will work best on any given day.

[rintinglen]

The only difference between my practice and Muskeg's is that I do preheat on a Good Will hot plate with a piece of scrap steel and a tin can on it to make an oven. This will get you good boolits quicker. When you start casting, go as fast as you can without smearing lead until you get light frosting, then moderate your casting speed slightly to get good boolits.

MP HP molds in my testing give you about 85% as many boolits as you get from a similar non-HP mold. I have a 452-200 HP clone of the H&G 68 as well as the same mold with no HP, both are MP manufacture 4-cavity and both were bought from the same custom batch. The difference is in the technique to invert the mold to assist boolit release and the occasional slight sticking of a boolit on a pin which requires an extra tap or two on the hing pin. These two issues slightly slow the production rate. But compared to Lyman, they are much faster, with a lower rate of culls. They are slightly faster than the NOE RG molds and produce somewhat fewer culls IME.