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Thread: Suggestions for a brass mold

  1. #1
    Boolit Bub
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    Suggestions for a brass mold

    I just received my first brass mold from MP. I have used several of their aluminum molds with great success but I have never dropped a boolit from a brass mold in my life. Any suggestions on break in or other things?

  2. #2
    Boolit Grand Master
    Mk42gunner's Avatar
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    Don't clean it within an inch of its life. Clean shiny brass is very easy to solder together.

    IIRC all the heat cycling hoopla came about because it is an easy way to get a bit of patina on brass molds, so the lead won't stick to the blocks. Consequently, I would clean any oils from it, then heat cycle it a few times before introducing it to lead.

    Good luck,

    Robert

  3. #3
    I usually clean mine, lube the sprue plate pivot and the alignment pins and pre-heat on high, for at least a half hour. I increase the melt temp about 35 degrees. start casting

  4. #4
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    I just wasted a half day with this MP brass mold. After 40 yrs of making boolits this is the worst mold I have ever had. I have an Aluminum from them and it was ok. At even 900 degrees I never got a frosted bullet and if it cools down for just one minute I have wrinkled boolits again. Maybe this is just a brass mold. This a convertible mold from flat point to hollow point and it leaks around the pin to make a burred nose. Oh yes I almost forgot it is heavy as hell. No mold should ever be made from brass.

  5. #5
    Boolit Master
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    There is a pretty good chance if you use it a few more times , & tinker around with it you will like it .

  6. #6
    Boolit Master

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    Well I have to agree that brass molds with more than three cavities gets a bit heavy. My favorite mold to run is a brass MP mold that throws 200 grain HG style SWCs. Once it is up to temp it runs great.

    I can imagine the hollow point versions are fiddly and slow the pace a bit too much. Speculating as I do not own one of that type.

    I just ordered a mold for .32 S&Wlong and got four cav aluminum. Probably could have gotten away with a smaller brass block pair in three cav but 4 hole aluminum was cheaper and usually give me no troubles. I started on mehanite molds, then brass, then aluminum. I kind of prefer mehanite but got sick of Lyman and other molds casting too small. Maybe I just buy guns that are too loose with the holes.

  7. #7
    Boolit Man
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    I used my 2 cavity hollow point MP brass mold for the first time today. I had a long learning curve. I have only used Lee molds before and they heat up fast.. Practically all of the 50+ bullets I cast with the brass molds had wrinkles. I used a charcoal pencil on the pins but the bullets wouldn't drop out! And so, I used a long nose pliers to pull them off. I used leather work gloves to push the sprue plate, picked out the sprues on top before opening up the mold. Casting was labor intensive. The mold wouldn't line up until I figured out that if I flipped the mold upside down, it would. I was about to give up but still persisted. I set the mold on a hotplate I bought while I cleaned up and then put the edge of the mold into the molten lead like I do with Lee molds and let it sit there for awhile. Then I reached for the hammer. With the mold hot and lead in the cavities, I hit the sprue plate to open it and the sprue pieces fell off. I didn't have to pick them out. I then tipped the mold upside down and tapped the mold handle ( not the mold ) and the bullets just dropped out. Since the mold was hotter, it closed easier. I repeated the process, swinging the sprue plate open as soon as the lead solidifed. At times the bullets did stick to the hollow point pins but I just kept taping on the handle and it eventually fell out. I think the key is to get the mold hotter than if you were using aluminum.

  8. #8
    Boolit Bub
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    I have not tried the hollow points yet. Putting in the pins for flatnose is what I wanted but pins leak which gives a burr on the nose. MP also sent the wrong top punch. I never got the mold hot enough as you all said. I never got anything but wrinkled boolits. I preheated the mold and turned the temp to 900 and never got it hot enough!! I made a mistake by ordering this but i guess we live and learn. Oh well it only equal to a few gallons of gas!! Yes I also got tired of Lyman molds that are too small, and gas check shank too big. Lee molds are usually too small and lube grooves not deep enough. It a gamble to buy one and get a good one. I will only buy molds from Accurate from now on. Iron and aluminum. I should have never strayed. I have bought many molds from Accurate and they are great. I wonder if I can throw this all the way to Slovenia?

  9. #9
    Boolit Master MarkP's Avatar
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    Did you try pre-heating the mold blocks? I preheat mine to 350 ish I have brass molds from Accurate and NOE RG (HP) and love them. Brass (Cu) has a high thermal conductively and the mold will have a high thermal mass. The blocks will pull the heat from the lead.

    What is the the bullet style?

  10. #10
    Boolit Man
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    Don't give up. Try it again but remember that it won't heat up quick like the Lee molds. I also was thinking of these molds like a heat sump. You can't wait too long between pours or else it won't heat up or lose its heat. If I had to set my mold down, it sat on a 1500 watt hot plate. When the pins are hot enough the mold is hot enough. Maybe think of melting a cold lead ingot into your pot and using a propane torch if you have to. This is about the time it takes to heat the brass mold. I plan to cast 9mm LHP MP bullets today. If so, I'll ask my daughter to take a video of it to show you.

  11. #11
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    Heat is your friend with a brass mold. I use MP HP molds often and I have only had a problem with an HBWC design. I preheat mine to at least 375 degree as measured on the sprue plate with a HF RF thermometer, either on the hot plate or on the top of my trusty LEE 20# pot. Then Once it is time. I start casting, I have had to resort to pencil lead on the Pins before, but only on the pentapoint ones. Since I normally only cast with the big pins, I seldom have a problem. I ran a set of side by side tests on two HG-68 clones, both 4 cavity, one HP and one solid nose. I get about 10 HP for every 12 solids per minute once up to temperature.
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  12. #12
    Boolit Master 5Shot's Avatar
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    What caliber?
    If you live on the razor's edge and slip, you will die in two pieces

  13. #13
    Boolit Man
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    I didn't cast today so I don't have a video. Instead, I decided to PC the bullets I had already cast.

  14. #14
    Boolit Buddy Gamsek's Avatar
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    All the “problems” that I might had with brass mould were solved with leaving them on a hot plate for 20 minutes. For some, setting on a hot plate must be at 75%max, for solid pistol mould I set on half (50%).

    I had to put on 90% for 390grs MP 477-640 (first time casting and no preparation not even cleaning it) because 75% was not enough. After proper preheating this is what I got


    I have over 25 MP molds, zero problems if you fallow instructions.

    A man crushed his new BMW. Never blamed the car. It’s the driver who failed.

  15. #15
    Boolit Master Wheelguns 1961's Avatar
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    There is a good tutorial about tips and tricks with mp-molds on their website. I highly recommend reading this. It really helps.
    Due to the price of primers, warning shots will no longer be given!

  16. #16
    Boolit Grand Master

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    Quote Originally Posted by flatnose View Post
    I just wasted a half day with this MP brass mold. After 40 yrs of making boolits this is the worst mold I have ever had. I have an Aluminum from them and it was ok. At even 900 degrees I never got a frosted bullet and if it cools down for just one minute I have wrinkled boolits again. Maybe this is just a brass mold. This a convertible mold from flat point to hollow point and it leaks around the pin to make a burred nose. Oh yes I almost forgot it is heavy as hell. No mold should ever be made from brass.
    Thanks for the heads up on weight . I have my first 4 cavity mould , an aluminum NOE and I thought it would be twice as heavy as a Lee 2 cavity mould ... No ! much heavier than that ..It's all the weight I can handle ...
    I appreciate you warning me ... I would buy something I couldn't use ...
    As for the weight thing ... get creative with holding and using supports ...do anything you can to take the weight off your hands / arms .
    I have no tips for using brass except contact the maker ... it may need a longer break in time / more heat cycles ... Good Luck .
    Gary
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    " Let's Go Brandon !"

  17. #17
    Boolit Master
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    I have a brass 2 cav hp mold from MP. Good hot preheat and pot temp about 800. The 2 cav drops the boolits easier than the 4 cav. Been using 20/1 without any lead sticking problems. The shallow cup point pins are easier to get good results from than the deep ones.
    "If everyone is thinking the same thing it means someone is not thinking"

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  18. #18
    Boolit Man
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    Mihec Cast Bullet Results.

    I used my brass 2 cavity 9-125 hp MP mold today. I had to preheat this mold much longer than aluminum and so I tossed back a lot of wrinkled bullets. My pot temp ran hotter than when casting with my Lee aluminum molds. Bullets stuck in the pins if I didn't let the bullet to solidify enough. Otherwise, as soon as the lead solidified on the sprue late, I opened the mold. To heat the mold, I placed the corner into molten lead. If I had to set the mold down, I am fortunate to say I have a hot plate. This is what the bullets look like. The 40-160 Mihec bullets I cast last week were shot two days ago at 18 yards and looked like this. I'm low on primers...Click image for larger version. 

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  19. #19
    Boolit Master


    Springfield's Avatar
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    IMHO, if you have to use a hammer to open the sprue plate you let it cool far too long. This is true with my LEE, Noe, Mihec, RCBS and Lyman moulds. I have 5 HP Mihec moulds, and I must admit they do take more care to get to work properly, but they work great once you get it figured out.

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Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check