Boolit weight different than specs for the mold

[468]

Just cast my first boolits with my “new” ideal 358429 mold. Just wanted to check it, and another mold out. I bought this mold used from a forum member here. Well, I had 0 rejects. None. Perfect projectiles. The info I’ve found show it was to cast @ 170g. Mine weighed 173 and change. Abt. 2% off. I figured that was within expectations.

So, I tried out my brand new Lyman 429667. My first time casting for .44. Was expecting 240g, as listed. My boolits weighed 252-253g...??? 5% out!

I don’t keep too close an eye on my alloy. It’s made from a mix of mostly clip on wheel weights, along with some stick ons, a piece or 2 of monotype, tin, ... unscientific and rather inconsistent.

I’m a hobbiest and don’t take this too seriously. But I would like the input of some of you more “anal” casters. What would cause such a deviation from the advertised weight? Mold cavities out of spec? Too much ... ???... lead is more dense than tin and antimony... I’m baffled.

[glaciers]

Well if you use a alloy that is relatively consistent, your bullets will be of a consistent weight, and that is what you need to use in you're equation. If your throwing what ever will melt together, there will not only be a difference in weight, but diameter as well. I consider the weight listed for a mold is at times more of a suggestion, although the custom mold markers hit it quite well with a given alloy as to weight and diameter. The RCBS 30-180 with my alloy of COWW plus 2% tin weights out right at 200 grains.

[Conditor22]

Bullet weight for a mold is determined by using a certain alloy within a certain temperature range.
You go with harder alloy you will get larger/lighter boolits
softer alloy will give you smaller heavier boolits

[StuBach]

I believe I remember reading somewhere that Lyman (and maybe the other makers too) typically use Lyman #2 alloy (90/5/5) to give a consistent rating when they create a mold (and then likely round to nearest convenient number for ease of marketing). I could be wrong in this though.

If your throwing mostly COWW and SOWW in the pot with some flavor adds your probably closer to 92% lead which would be heavier for the same volume.

As mentioned by others, temp of cast can also have impact.

[44MAG#1]

If you have been casting long, which you haven't, then you would know this is more common than uncommon.

[trapper9260]

Also when you see the mold listed , look to see what alloy they used for the weight, also dia., like was stated already go with that also. For me I try to get the same mix of alloy and get close to the same and then go from there.

[468]

44MAG#1, I actually have been casting, sporadically, since the 70’s. Back then, it was .38/.357, and .45’s. I competed in the early local IPSC competitions. Casting and reloading was the only way we could afford to play. (“We” because I was pretty much taggIng along my eldest brother and, being in my teens, had no money)

The last 10 years, mostly for .45 and .40/10mm. The 2 molds I use for the .45 are within 2-3 of expected weight, usually heavy. The 2 molds for the .40/10 are +/- 2g. The .38 mold is +3-4g.

However, this is my first attempt at the .44. I initially thought the heavier weight would account for the differential, but my .45’s are 225 and 230g. So, there goes that theory. I don’t have the info to do a calculated comparison using the density of pure lead as the heaviest option, and working backwards from there.

After reading info above, and even my own comments, It’s got to be the mold.

Thanks to all.

[44MAG#1]

44MAG#1, I actually have been casting, sporadically, since the 70’s. Back then, it was .38/.357, and .45’s. I competed in the early local IPSC competitions. Casting and reloading was the only way we could afford to play. (“We” because I was pretty much taggIng along my eldest brother and, being in my teens, had no money)

The last 10 years, mostly for .45 and .40/10mm. The 2 molds I use for the .45 are within 2-3 of expected weight, usually heavy. The 2 molds for the .40/10 are +/- 2g. The .38 mold is +3-4g.

However, this is my first attempt at the .44. I initially thought the heavier weight would account for the differential, but my .45’s are 225 and 230g. So, there goes that theory. I don’t have the info to do a calculated comparison using the density of pure lead as the heaviest option, and working backwards from there.

After reading info above, and even my own comments, It’s got to be the mold.

Thanks to all.

Just do yourself a favor and don't over think things. Just cast a Batch of bullets that will last a while and load and shoot. If one batch weighs a couple light and a batch is a couple grains heavy don't sweat it it is still the same bullet. The design hasn't changed. Probably 90 percent of ALL SHOOTERS arent good enough to tell the difference. This is based on seeing Master Class Bullseye shooters on down to just pure beginners shoot. Minor differences make no worthwhile difference.
If you believe it does load a batch of two weights of the came bullet that has a difference of let's say two grains from average each way. Load them with your best load, take a friend to load your gun without you knowing which batch it is and shoot from field positions and report back. Now do a good test not a 5 or 6 shot test of each but lets say four 5 or 6 shot groups each. Tell us if you can tell any WORTHWHILE difference.
Unless you are a phenomenal shot you won't be able too.
Try it.

[mdi]

QUOTE]Conditor22 Bullet weight for a mold is determined by using a certain alloy within a certain temperature range.You go with harder alloy you will get larger/lighter boolits
softer alloy will give you smaller heavier boolits[/QUOTE]
This^ I believe Lyman specs their molds with Linotype and Lyman #2. The Lyman manuals note what alloy is used for the bullets tested and the 429667 is listed at 240 gr with Linotype...

[quilbilly]

As long as your weights and alloy are consistent, that is what you want. No worries.

[468]

I think I’m going to do 44mags suggested test. I am almost certain I will not be able to tell the difference.

The loading data for the powders I use overlap for 240g and 250g, so I can load without concern.

[OS OK]

Study this chart carefully, it explains what you are seeing now and will soon see when you size them and see another difference.

[charlie b]

More important, what was the diameter of the bullets you cast and were they round? You may have a mold that is casting oversize or oblong that might help account for the extra weight (along with different alloy).

[Harter66]

I have a Mountain Molds 453-350 cut for WW+2% tin it drops .453-354 with 1-20 and .453- 350 on WW/1-20 @ 75/25 . I can live with that .
My Lee 452-255 RNFP , 2 different moulds , drop .454-265 with 50/50 WW/pure and 263gr on straight WW . I know adjust loads and go .

The Lyman 457193 , a 405 gr , drops 50/50 as above at 415 gr .
Same alloy in an MP 462-420 drops .460-417 .

I have a HB Lyman that is supposed to be an original style 454 dia HB @ 255 gr for BP 45 Colts in SAA and Peace Makers drops .454 ok but at 285 gr with 1-20 .

Unless it's a semi or full custom the weight a mould drops is a guess at best and you get what you get with your alloy .....

[kevin c]

If they shoot well in your gun without causing any issues, then it's not of much concern. You may recall from your IPSC days that bullet weight times velocity had to make power factor, but, outside of that, I can't think of a situation in which a specific bullet weight might become a major issue.

[facetious]

I have a .30 cal mould from LBT that will go from 165 gr's to 168 gr's depending on the alloy. They all shoot the same. I try to cast in large lots so I can go for a while with one alloy .

[jsizemore]

I could be wrong but didn't ideal/lyman figure their weights with lyman #2 alloy? If your at all concerned with load data go to the next bullet weight up and use that load data.

[robg]

as long as they are consistant and shoot well dont worry.

[bedbugbilly]

468 - I'm pretty "low tech" when it comes to mixing alloys . . . you probably are more advanced than I. I primarily use range lead . . . if i want a batch a bit harder, I toss in a little ingot of foundry type - a accumulated several five gallon buckets of it probably 30 years ago and smelted it down and made muffins out of it - like I said . . . I'm "low tech". I have accumulated quite a few molds of all makes over the years and I find it interesting on how the boolit weights vary from what the mold is supposed to cast - but as mentioned - I believe they are designed for a particular alloy.

All that aside though . . . . at least your molds are casting the right diameter. Several years ago, I purchased a used but like new single cavity Lyman hollow base minie mold that was supposed to cast a .44 diameter boolit. I needed it to use in a particular BP rifle that I had that had a Numrich barrel on it. I got the mold - looked great - had all the correct markings on it . . . so I set up to cast. It was nice day, I had the garage door open to enjoy the weather and the mold dropped 'em like butter. They looked great and after I had a couple hundred cast up . . . I took a break. I decided to get the rifle out and check how they fit in the muzzle . . . what?????? I couldn't have gotten them in with a shoe horn and a hammer. LOL I grabbed my digital calipers and pulled out a dozen . . . . my .445 boolits ALL measured .452! That little exercise taught me a good lesson . . . cast a few and measure and weigh. Obviously, my Lyman mold had been "mis-stamped" at the factory . . . . and I'm guessing that the guy I bought it from knew it too. I found another .445 mold a couple of weeks later and it cast great for the rifle. The "mis-marked" mold that cast at .452 wasn't a real loos though as I kept it and have used it a few times out of a 45 Colt and they shoot pretty well.

Nothing to do with grain weights being off but when buying a used, or even a new mold, it pays to run a few and check out the diameters and weights as mistakes do happen as far as mold matings. For the type of shooting I do, a variance in grain weights really has no effect but I''m sure that a serious competitive shooter may see it otherwise.

Because of my individual "low tech" approach and the variance of the alloys I'm casting from one batch of range lead to another, I would say that for me, a 2% to 5% variance from the "intended" grain weight that a mold is supposed to cast at is probably pretty much the norm, both for pistol and rifle boolits.