trouble casting .22 boolits

[Patrick L]

Guys,

i think I need a little advice. I finally took the plunge and began casting for my AR. I just received a beautiful Mihec brass 22 NATO 4 cavity mold. It is a work of art. I am a veteran caster, but have never cast a .22 boolit before.

Anyhow, I was visually inspecting my first casts, and I notice my boolits seem "bent". I paid attention during my second casting session and looked at the bases in the mold before I opened the blocks. The boolit bases are away from one side of the cavity and shmooshed tight against the other. The boolits are tight against the side the sprue cutter swings toward, and away form the side it comes from. I think the impact of whacking the sprue cutter is forcing the boolit bases to one side. I think the main problem is that on a .22 the sprue hole is almost as big as the whole base, unlike a .38 or .45, or even a .30 for that matter.

Is this going to be an issue? I'm sure sizing and gas check installation will true things up, but I always believed you didn't want to rely on a sizer die to fix defects that shouldn't be there in the first place.

Your thoughts?

[Ben]

You may be trying to open the sprue plate too early ?

[HARRYMPOPE]

If the sprue hole is that large it is an error in the sprue design.I have a .225415 Lyman that was like yours and replaced it with cutter from another mold that had smaller holes and the bullets bases were improved.Open the mold with a thick leather glove(with a slight downward force) and you also can solve this a bit.Just be careful and pay attention to your glove wear.

[Mark85304]

I find that my MiHec 5.56 NATO mould likes to run hot which necessitates a longer cooling period for the alloy to set in the mould before removing the sprue. Remember, this is a brass mould and will hold heat much better than aluminum moulds so be mindful of how long it takes for the alloy to solidify and adjust your casting cadence accordingly. Additionally, you may be running your alloy too hot. If you cut back your heat after your alloy goes liquid and your mould gets hot, not only will you be able to cast longer before the heat becomes an issue, you will likely drop better boolits.

[Piedmont]

You didn't mention your alloy and I suspect this is an alloy issue. Put more antimony in there, if I am right. Were you using lots of pure lead and a little tin? A larger sprue hole will allow the plate to pull the base away from edge just as you have mentioned when using a soft lead/tin alloy.

[John Boy]

I cast pure Pb Lyman 225438's for BP 22LR reloads ...
* 5 second pour
* Pot temperature so sprue puddle frosts in 5 second - is KEY to insure that bullets have solidified fully in the mold
* Then lightly tap the screw on the mold handle - this releases tension between the mold halves
* With your stick, push on the bottom of the right hand mold half. This releases the adhesion between the 2 mold halves so there is no torque opening the mold

Bullets will have a concentric axis and will not be bent

[Patrick L]

Good advice all, and I thank you. Alloy is WW with about 2-3% tin added. I don't think I'm opening too soon, I always cast with 2 molds so the filled one sets before I pick it up to open it.

I was running the pot pretty hot as previous reports on this mold said it liked to be run hot. I think I'll turn it back down to where I normally cast at.

Thanks again and keep the replies coming!

[.22-10-45]

Hello, Patrick L If your sprue hole is indeed too large..as I have found in some original Ideal and Winchester moulds..you can use the old Ideal dodge..written up by John Barlow..position cuttter so 1/2 or less of sprue hole is over cavity..I have done this with original Ideal 22636 & some .25 Ideals..those sprues were nearly as large dia. as base..base is nearly smooth and flat as a nose-pour.

[badbob454]

Hello, Patrick L If your sprue hole is indeed too large..as I have found in some original Ideal and Winchester moulds..you can use the old Ideal dodge..written up by John Barlow..position cuttter so 1/2 or less of sprue hole is over cavity..I have done this with original Ideal 22636 & some .25 Ideals..those sprues were nearly as large dia. as base..base is nearly smooth and flat as a nose-pour.

this is a good suggestion i wouldnt have thought of......hmmm

[HARRYMPOPE]

22-10-45
its a 4 cavity and probably wont work.I use the offset cutter also on Lyman SC molds with big sprue holes.Cant prove it gives better groups but it makes me feel better.Jim Carmichael(or Wooters?) wrote it up as well in Handloader.

[runfiverun]

quit whacking the sprue plate.
just open it by hand before the lead sets up hard enough you have to whack it open.

[cbrick]

Alloy is WW with about 2-3% tin added.


I was running the pot pretty hot as previous reports on this mold said it liked to be run hot.


If your running your pot anything past 750 degrees you might as well save your tin and not put it in. The metallurgy of Pb/Sn alloy is that Sn cannot do what you put in the melt to do past 750 degrees.

Small bullets do indeed need more heat BUT it's the mold that needs to be kept at proper casting temp . . . NOT the alloy in the pot kept high. If your molds proper casting temp is as high as 425 degrees, most likely it's less but even if it is that high if your pot temp is 725 degrees that is far more heat than needed to keep the mold at three hundred degrees less. Cooking the Sn out of the alloy is the lazy man's way of getting the mold to proper temp, for me high quality boolits is much more important than simply making it easier.

Pre-heat the mold simply to save the time & number of pours it would take to get the mold to proper casting temp. Once you start casting don't look at it as pouring alloy into the mold, look at it as pouring heat and a 22 boolit doesn't pour much heat so you need to adjust the casting pace to pour more heat. Don't pause to inspect & admire the boolits, keep casting. I also cast at times with two molds but not with the 22 boolits. Casting 22's keeps me plenty busy with just one mold. Also pour a very generous sprue puddle to keep the sprue plate up to temp.

As was already said, use a gloved hand to open the sprue plate and lower the pot temp, that will save your tin AND reduce the time for the alloy inside the mold to set up. It's not just the sprue puddle that's outside of the mold and in contact with the air freezing, the alloy inside the mold must also be set up and it takes much longer to do so from 850+ than it does from 725 degrees. It's a practiced timing thing, proper pot temp, proper mold temp and timing to open the sprue. It's not difficult but does take some practice, more so with tiny boolits but the results will be worth it.


I'm sure sizing and gas check installation will true things up, but I always believed you didn't want to rely on a sizer die to fix defects

No, a defect should not be covered up with a gas check or by sizing or with lube. A defect is a defect whether you can still see it or not and the tiny boolits are more effected by minor defects than larger boolits.

Rick

[JeffinNZ]

This is what I made for my .22 moulds. Much reduced extreme spread in boolit weight and better bases.

http://img.photobucket.com/albums/v505/JeffinNZ/Shooting%20stuff/225462.jpg

[David2011]

Sounds like a little Bullplate lube might help. It allows you to open the sprue plate almost immediately after pouring, using only a glove, while the lead is still very soft yet it prevents the lead from smearing on the sprue plate and the top of the mold. Boolit bases are much better with Bullplate lube.

David

[popper]

The metallurgy of Pb/Sn alloy is that Sn cannot do what you put in the melt to do past 750 degrees Huh? I guess this is right if tin is used for better fillout, not hardening.

[cbrick]

Huh? I guess this is right if tin is used for better fillout, not hardening.

Tin will harden lead, just not very much. Much better/cheaper ways such as antimony.

Rick

[fullofdays]

i had a related issue today. I was having issues with the sprue not cutting clean on my mihec Nat 4 cavity mold. tried the pot temp from 700-760 and everywhere between. tturned out, the bent washer holding the tension on the sprue plate was entirely too high and was angling the plate a hair OD the top of the cavities. glove hand works when opening!!! proper sprue plate tension is important on this mold....

http://img.tapatalk.com/d/12/12/09/ysyvupy9.jpghttp://img.tapatalk.com/d/12/12/09/eta5uger.jpg

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[leadman]

Also check the base of the holes in the sprue plate. Make sure there is not a straight saction from the taper not being cut deep enough in the plate. Lyman is notorious for this, one of the first things I check on the molds I get. Instead of a knife edge it is blunt and breaks off the sprue rather than cutting.
I use a 45 degree countersink from Home Depot to finish the taper. Doesn't match up perfect but this causes no issues.

[madsenshooter]

Though I haven't got to cast with it yet, I foresee similar problems coming with a NOE MX3-225-EX. The sprue holes are .140" or so . Oddly, I ordered a 6mm version of the same mold and it has smaller sprue holes. I like Jeff's.

[JeffinNZ]

My pouring holes are 2mm. Small but they work great.