HELP MiHec 359 125 fill out around the hp pins

[remy3424]

I have been fighting my brass 359 125 MiHec mould on complete fill-out on the tips around the pins. I have cleaned it multiple times, dawn and a tooth brush, brake cleaner and boiled it. It seems to be a bigger problem with the penta pins than the round pins, but that might just be more noticeable on the penta pins bullets. I started with about 50/50 coww and soft lead. I added some 40/60 tin/lead and it seemed to help some, I just am a little concerned with soldering the brass mould. I ran temps from 700 to 800. One strange thing that I notice when I switched from the penta to the round pins was the bullets were sticking in the cavities much more when using the round pins...weird. I have a 45 cal semi wad cutter MiHec brass mould that fills great once I get frosted bullets. Even at 800 degrees I didn't get a frosted 9mm bullet.

Searching threads lead me to cranking up the heat and adding the tin. I would like softer bullets with the hollow points but I am not sure I can get there.

Any ideas? More heat, more tin? I know there has been several run of this mould. Is anything working for you with the penta pins in this 9mm mould?

[Bullwolf]

If the Hollow Point pins cool off, I get fill out problems, sticking, and wrinkles around the H.P. cavity area.

The H.P. pins are small, and they seem to shed heat faster than the mould does.

I like to polish, or lap my H.P. pins, so I know they're smooth and boolits wont hang up on me. I don't use oil, or any other kind of mould release on the pins, or else I tend to have H.P. cavity wrinkle problems

Keeping a hollow point, or hollow base mould's pins warm is a challenge in speed casting.

Opening the mould for too long, or stopping to look at things lets the pins cool down, and then you will get poor casts. Unfortunately most hollow point mould set ups take longer to cast with simply due to the design, which often exaggerates the problem.

My solution was to use an electric hotplate.

http://castboolits.gunloads.com/attachment.php?attachmentid=114714&d=1409027142

I use a inexpensive electric hotplate as a mould pre-warmer. It heats the mould to casting temp, and helps maintains that temperature nicely. It's much easier than running a stupidly high alloy temperature, in hopes to heat your mould up more.

If it's windy, or freezing outside when you cast, the mould oven top (coffee can) helps bunches. If not, just setting an old skill saw blade on top of an electric hotplate works fine.

I use the hotplate to pre-heat my ingots, and to season new moulds with as well.

When using a hot plate you don't have to cast a bunch of reject boolits, while trying to heat up your mould. Your first casts will often be keepers as everything is already up to casting temp from the start.

If you pause or stop for some reason, set the mould back on the hotplate and it stays at casting temperature, and you can resume casting right away.

Using a hot plate changed the way I cast boolits (for the better) especially hollow point styles.


- Bullwolf

[runfiverun]

the problem isn't the alloy temp [which is too high]
it's the mold/pin temp.

turn the heat down and just cast with the mold don't even look at the boolits until you get 20 good quick casts in just cast and dump and cast and dump.
keep the mold closed as long as possible and get some heat built up in it.

[44man]

That is right, Big brass molds need to be kept hot, not so much the lead pot but speed of casting.
Gets my arms tired but they can be made to work and are jewels of machining.

[remy3424]

I am currently using a hot plate on medium temp, I cast as fast as I can get the bullets to drop. Maybe cranking up the plate to high temp could help. The thought I have now is to try clean up or polishing the pins at the base of the points, that is where the problem is, not in the brass mould. Another suggestion was trying pressure feeding the mould...I am using a Lee 20 and a PID, dropping only three quarters of an inch, no breeze or wind to cool things off.

[W.R.Buchanan]

I ran into this when I started with my first Brass mould. The problem was, as stated above, The pins weren't hot enough.

On your initial heat up to casting temp of the mould on your hot plate,,, the pins don't heat up as fast as the rest of the mould. They are Steel and don't conduct heat as fast as the brass does.

If you heat the pins with a small butane torch (Don't go Ape here!) it will bring the pins up to the temp of the mould itself.

This will make it so the boolits drop off the pins and you will get a complete fill.

Worked for me.

Randy

[remy3424]

If you heat the pins with a small butane torch (Don't go Ape here!) it will bring the pins up to the temp of the mould itself.


Randy

I will try this.