Problem Mould #2

[Creeker]

Over the last month or so I've been in conversation with the owner of a 6 cavity aluminum MP HG68 BB mould. I was told the mould only produced one good bullet of the six. The bad bullets displayed a slightly deformed nose & a place on the driving bands if memory serves. The owner tried many things to cure the problem such as smoking the mould different ways etc. We spent a couple phone calls on this mould & finally yesterday the mould was in my presence to try.

I woke up this morning to a storm & thought it a fine time to cast some bullets. I placed a few pounds of alloy in the pot, set the mould on top the pot & inserted the plug in the wall & walked upstairs to pancakes & eggs thanks to my wonderful wife.

After the meal I walked downstairs, inserted the tip of the mould in the melt for maybe 5 seconds & began. Took about 3 or 4 cycles & the bullets looked good. I did nothing to the mould only cast as it was given to me. I believe the problem was heat. Either his alloy wasn't hot enough or he was casting too slow. I'll enclose some pictures.

Mould






The sprue plate was loose & if I didn't use care cutting the sprue I had this.


This mould was new to me so it took some cycles to get my timing. Not fast enough here, notice the rounded front band.


A perfect base.


The bullet.

 

[Rick]

Many people accustomed to iron molds have big trouble when going to aluminum and blame the mold or the mold maker. Aluminum is an excellent mold material but like many things there is a learning curve. Which reminds me, I have got to get that mold sent back to you. Wow di I ever drop the ball on this one. My apologies.
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[Creeker]

Still haven't shot all the bullets I cast with the NEI mould but what little I've shot did fair.

 

[Ian]

Creeker, I have a very sour taste in my mouth still from my particular MP 45-200-SWC (4c, brass), mine came with an "impossible" machining defect which to this day still baffles me. The meplat of each cavity had three little bumps in it which made dimples in the meplat, and that combined with the little to no draft angle on the front shoulder effectively locked the bullets in the mould blocks until they received severe beatings. It took me hours with an Xacto knife and tiny files to finally get them knocked down. Here is a pic of some of the bullets cast from it before I fixed it, notice the dimples and the grooves leading away from them as the bullets were literally torn out of the cavities.

 

[Creeker]

Creeker, I have a very sour taste in my mouth still from my particular MP 45-200-SWC (4c, brass), mine came with an "impossible" machining defect which to this day still baffles me.

That had to take a bunch of work on your part.

 

[Creeker]

Here's the bullet both dressed & necked.

 

[Brad]

Nice looking bullet. My 4 cav brass is a flat base. Unlike Ian's mine drops very nicely. I do get a few rounded front bands at times. Since I went to a ladle those are largely a thing of the past.
Only issue I have is the weight. A 4 cav brass mould is heavy.

 

[Rick]

If you think a brass 4 cav is heavy now just wait another 20 years and see how heavy it is. All of my Miha molds are brass four cavs and I am definitely questioning the wisdom of that.
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[Brad]

Rick, you are a far bigger guy than I am. I question the wisdom already. If they didn't cast such a fine bullet I would be rid of them.
The 311410 HP is unique in that it is heavy AND requires the calisthenics to drop the bullets off the pins.

 

[358156 hp]

I sold off my Lyman 4 cavs because I kept getting muscle pain in my shoulders. Now that money is getting back to normal, I'm replacing the Lymans with NOE & LBT 4 cavs. So what did I just buy? Another Lyman 4 cav! The real problem here is that I really like the older Lymans. I do swear that it seems to take longer to burn the cutting oil out of aluminum than it does with steel. NOE especially. I do finally get it done, but I have to give up at least twice before the mould comes around. Ians suggestion of smoking the cavities was really helpful on the last one, even though the experts at CB told me only fools smoke moulds. I don't miss them at all.

 

[Rick]

I don't smoke molds, not NOE not aluminum not any. For those that think it's a worthwhile thing have it but the truth is if it helps at all it is only covering up a problem. For me finding and correcting the problem is a much better solution. Most problems are the mold isn't clean and/or not hot enough. Burs are a possibility but with over 70 molds I haven't encountered that in the 20 years or so that it's been since I stopped buying LEE molds.
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[gman]

I've learned to scrub my new NOE molds very well with dawn and rinse them in hot water. I then run them through 3-4 heat cycles on my hot plate before actually casting. If I use my patience and do this they work perfect. No smoking needed on mine.

 

[Ian]

The 311410 HP is unique in that it is heavy AND requires the calisthenics to drop the bullets off the pins.

That's a fact, Jack. Ran a full 20-lb pot of those a few weeks back and OMG. At least the mould worked with no fuss, no sticking, and no drama, but yeah, there is some Sumo Acrobatics going on to flip the mould over to drop the bullets. And if you slack the pace with tin-weak 50-50 alloy, it starts to wrinkle or get pockets around the tip of the hp pins, so it's a full hustle.

 

[Ian]

Oh yeah, smoke. I use it mostly to expedite break-in, some aluminum moulds like Tom's don't seem to need it, some do, Lee practically requires it. I'm talking the faintest haze of smoke, like just a light tan hint. If there's any black, dust it off with a camel-hair brush. I also use a little smoke on brass moulds to avoid the pre-patina tinning in the cavities. A trick with MP aluminum moulds (as I've seen but not yet done) is boil in detergent/water for a while and they will get a light, dull grey patina all over which basically is a speedy break-in.

 

[gman]

My mold for that bullet came from Accurate. It is quite amazing the ease at which it drops bullets.