Mould & Casting Question


September 1, 2004, 10:16 AM
Lyman moulds 429667 & 457125. Two questions.

1. What weight, from what alloy, do they come from the mould?

2. What diameter, from what alloy, do they fall from the mould?

Thanks and God Bless.

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September 2, 2004, 07:18 PM
The first three digits of Lyman bullet molds are the bullet diameter with the last digits denoting the shape or cherry number. All weights are in Lyman #2 alloy unless notes otherwise by Lyman.

Mold number 457125 is a 500 gr. roundnose bullet.

Mold number 429667 is a 240 gr. flatpoint for cowboy action shooting.


September 2, 2004, 08:50 PM
Thanks Bruce. I should have asked this differently. I have the information you gave. I was looking for someone who uses these moulds for a report. We've had trouble finding moulds that would cast close to advertised weight and diameter. I was hoping someone was using current production runs so I could pick their brain.

September 2, 2004, 09:43 PM
Regardless of what mold you use, the diameters will vary slightly. Bullets will drop larger or smaller from the same mold depending on the hardness of the alloy. Generally, the harder the alloy, the larger the bullet. Also, two molds of the same number will drop slightly different diameter bullets when using the same alloy because the cherry used to cut the mold can be in different stages of "wear" and still be within the manufacturer's spec.

Regarding how a particular bullet will shoot, it can vary from gun to gun, the alloy used to cast the bullet and/or the range you're shooting groups at.


Jim Watson
September 2, 2004, 09:43 PM
I cannot help with those two specific bullets, but with a mold I bought last year, Lyman 378674, nominal .378" 335 grain; mikes .379" and weighs 337 grains out of 20:1. Older molds were usually oversize but this one is pretty close.

September 3, 2004, 06:42 AM
We have two Silver Star moulds from Lyman. One in 38, the other 45. The 38 cast almost 10 grs. heavy while the 45 in right on the money at 250 grs. The diameters of both are plenty large enough.

The Lyman 457125 bullet is one I'd like to add to our company. If I thought the mould would cast close to standard weight and of large enough diameter it could be sized .460 I would buy a couple of these moulds in a heartbeat.

We understand the difference in diameters and weights when it comes to different alloys and the alloy we cast is close enough to Lyman No.2 it would be no concern.

I'm aware of the numbering system also and a as cast diameter of .457 won't get it for a 45 caliber rifle bullet.

I've had little luck discussing these things with the Lyman tech or RCBS for that matter. The troubles I had with RCBS and their 44-250-K mould would fill several pages and I'll not go into it here.

I thought if someone was using current production of the moulds mentioned they might enlighten me.

I might be better served using a custom mould maker.

September 3, 2004, 08:13 AM
Gents...May I hijack the thread for a few minutes?

Bullet alloys not only determine the hardness of the finished cooled bullet, they often determine bullet quality.

A few things to keep in mind:

The numbers on the mold are nominal. The bullet will generally fall out of the mould from .002-.004 inch oversize. You determine the final diameter with the sizer die.

The addition of tin causes the alloy to flow more freely and fill the mold
better. It also works to prevent voids in the bullet...both on the surface and below.

Antimony is an alloyable metal that does two things to the lead. It hardens the mix...but it needs tin in order to mix freely with lead, and without tin, it will settle in pockets. Tin is the key to using antimony,
and the best results are obtained when the two are mixed in equal amounts with the lead. Lyman #2 is a 90/5/5 Alloy...90% lead with
equal amounts of tin and anitmony. Taracorp is 92/4/4 by weight, and both will produce excellent bullets. Wheelweight alloy averages
95% lead, 4% antimony, and 1% tin, and needs a little more tin to make
good quality bullets. Dutch Boy 50/50 wire solder is available in one-pound rolls. Keep in mind that a certain amount of tin is lost during the smelting of wheelweights...and if the melt is allowed to get too hot for too long a period of time, you can lose nearly all of the tin in the alloy.

Antimony has the unique property of expansion as it cools and solidifies,
and this expansion sometimes continues for several hours or even days
after the bullet is cool enough to handle. For this reason, it's generally better to wait for 24-72 hours before sizing bullets with more than about 2% antimony.

Lawrence brand #8 shot is about 7.5-8% antimony with almost no tin, and
is an exonomical source for antimony, but remember to figure the amount of antimony by the weight of the shot that you add to the mix, and try to keep the tin content within 2% of the antimony content. Too much antimony to tin will produce voids in the bullet unless temperatures are kept fairly high....and the higher the temp/time, the faster you lose tin.

I recommend smelting and alloying be done in a separate operation from molding. Alloy your mix and pour it into ingot molds, and flux it often. You
can make ingots with a 3-dollar muffin tin just as well as with an expensive ingot mold unless you need to keep your ingots consistent in weight.

As you melt your prepared ingots to make bullets, add about an inch of wire solder to the mix every 30 minutes, and if accuracy is your goal,
ingot the last 2 pounds in a 10-pound pot and separate these from the bulk of your pre-made ingots for use in a separate lot of alloy. The slight difference in finished weght and hardness between the two lots won't amount to any practical difference in performance, but it will keep your
bullets more consistent in each lot.

Lastly...Don't get too hung up on hardness. Leading isn't caused by soft lead, and the hardness is mainly needed to make the bullet take the rifling
without skidding. Leading is caused by gas cutting past the side of the bullet, and melting of the lead at the base and sides. Bullet sizing is what
keeps leading down. If the bullet is too small to seal the gasses off, or too hard to upset and seal the bore, it will lead no matter how hard it is. I use the same alloy for 230-grain .45 ACP at 850fps and 160-grain .357 Magnum
at 1300+fps...The slower bullet will lead, while the faster bullet won't lead at all, beyond a light lead wash that comes out with 4-5 passes with a brush and Shooter's Choice solvent.

You'll love bullet moulding, but be careful with it. Wear protective clothing and especially heavy gloves. A dime-sized dollop of hot lead on your hand will make you wish that you were someone else for about 30 long seconds,
and it will take 3 months to completely heal.



Jim Watson
September 3, 2004, 08:17 AM
My BPCR coach has gone 'round and 'round with two different custom bullet mold makers. Bullets are clean and precise, but they do not drop free and are a constant aggravation. He has a couple of Lymans and I have the one that are not as precise but are a lot easier to use.

Another shooter I know has a mold from one of the same custom shops that is a real jewel, so it is a bit of a crapshoot no matter what you buy.

I'd try a Lyman and bet the $46 that it would do you.
If it didn't, I'd talk to Paul Jones.

September 3, 2004, 09:31 AM
Any bullet mold that drops a bullet more than .002" oversized either goes back to the manufacturer or to the junk heap IMHO. That's because swaging the driving bands down that amount during sizing will soften the bearing surfaces and cause leading. Even .002" large is an marginal situation.

All bullets with deep, square grease grooves and driving bands have a tendency to hang in the mold in my experience and it can be a real pain, especially so to a volume or commercial caster. RCBS 44-250K, Lyman 429421 and similar shapes can be especially testy.

Leading of the bore and cylinder mouth can be caused by a variety of reasons including bullets which are too large, too small, eccentric, too soft, insufficiently or incorrectly lubricated. A small amount of leading always seems to occur but it should be easily removable with ordinary cleaning procedures.

For what it's worth.


September 3, 2004, 10:03 AM
Bruce said:

because swaging the driving bands down that amount during sizing will soften the bearing surfaces and cause leading.

Howdy Bruce, and welcome to THR. Good to have another lead-head aboard.

I only have that problem when I size the bullets too soon after molding.
If they age for 3-5 days prior to sizing, they don't soften much, and even when they do, further aging lets the skin harden back up a little after sizing, depending on the tin/antimony ratio. Slightly higher antimony
hardens, while slightly higher tin softens a little with age...about 6 months
tells the tale. For bullets that I intend to store for a year, I bump the antimony up a little.

I agree that more than .002 over what I intend to size'em to is too much, though...but I generally size .002 over groove diameter instead of .001 inch unless I use a gas-check bullet. I get less leading with a bullet that seals the bore early, and I can't really tell a difference in accuracy with plain-based pistol bullets. I do see a huge difference in leading though...



September 3, 2004, 10:42 AM
Below is my question and Lyman's answer. I have no orders for .457 or .458 bullets, they've all been for .459 or .460. I want to make this old classic bullet but if the bullet isn't large enough it would be useless.

From: Date: Fri, Sep 3, 2004, 9:41am To: Subject: Re: Data posted to form 1 of

The spec of the 457125 bullet mould diameter is .458 to .460 with #2 alloy. We cannot guarantee it will be on the high side for you. This will somewhat depend on the alloy you are using as well. There can be as much as a 5% variation in weights in this bullet, again, alloys will affect this as well.

An example would be with more lead or wheelweights, the diameter would be smaller but it would be heavier. The addition of linotype would cause the bullet to be lighter and the diameter larger. Hope this information helps you.
Thank you,
Lyman Customer Service Dept
---------- Original Message ---------------------------------- From: (lyman1) Date: Fri, 3 Sep 2004 11:21:19 GMT

I'm the owner of Dry Creek Bullet Works, Inc. At present I use several Lyman moulds. We want to add a new rifle bullet to our catalog. We are considering the L-457125. I've cast bullets for over 30 years so I'm well aware of the effect alloys have on diameter and weight of a given bullet.

Here's the questions:

Will Lyman mould 457125 cast a bullet of large enough diameter from your No.2 alloy, that the bullet may be sized .460?

What are your highest and lowest acceptable weights for Lyman mould 457125 when cast from your No.2 alloy? We aren't speaking of bullet weights from the same mould, but normal production runs of a group of these moulds. I've had moulds of the same number and manufacture that would cast 15 grains apart.

Thanks for you time and I'm looking forward to your reply. God Bless.
Lynn & Barbara

Jim Watson
September 3, 2004, 03:51 PM
I was out with my BPCR mentor today and asked him.

He says his Lyman 457125 casts out at .459-.460" depending on alloy and temperature, but weighs about 520 grains. He said he has never heard of anybody with a 125 that cast as little as the 500 grain catalog weight. On the other hand, his 457124 is well under the listed 400 grains... but is the same diameter.

We are pan lubing our bullets with SPG for black and do not size. He sized some .40s from as cast to .408" or .409" and they didn't shoot worth a hoot.

September 3, 2004, 08:44 PM
Thanks Jim. I have a few here cast from I don't know what. It's a beautiful bullet but it's heavy also. In fact about 520 grs.

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