reporting your mold drop size

[soldierbilly1]

I have noticed that many report their drop size on a mold, say, as 0.358."

They do mean this as an average, correct? the real drop size is more like .357 - .359"? true??

I find I need a minimum of .3580" ( 4 sf with micrometer) to avoid leading in my Ber 92. I really need to "drop at
0.359"" to get that.

To avoid confusion, this measurement is critical, I think we should really report a range. My usual range is about +/- 0.0006" about the average.
just a thought

billy boy

[Love Life]

I'm not sure what you're asking. When I list a mould drop size, it is the size that actually drops from the mould...as measured with 2 different micrometers.

[soldierbilly1]

Is it an average? Billy

my .358 drop is really 0.3575" - 0.3585" based on about 10 boolits.

[Mk42gunner]

My micrometer only measures to the thousandth, or third decimal place. Any further is just guessing.

If you are getting diameter swings of up to two thousandth's of an inch, you need to look at your casting methods. Consistency is what you need.

Robert

[ShooterAZ]

The size dropped from a specific mold, for me anyway, will vary depending on the alloy used and the temperature cast. Higher antimony alloys tend to cast a bit larger, and even expand a tad after being cast. To answer your question, I would say +-.001 or more...depending.

[Blammer]

I don't need to measure it, my mould drops at the size it say's on it. :)

[prs]

Consistency and redundancy; two of our very best friends!

prs

[gray wolf]

If you tell Tom the metal you are using and the size you want it, he will make you a mold that is guaranteed to be
-0 +.002 and you will have a beautiful brass mold. you will have to size to your specific size if it's critical.

[shredder]

Mmmmmm Big ol' can o' worms here! First off I really like this idea. I have record of this information for all my moulds.

As previously mentioned so many things can influence that final diameter it would be helpful to clear up some of the criteria. First we should be talking about the same alloy, as that can really skew things. Linotype is standardized so that would be a great reference alloy.

Then it would make sense to state the approximate age of the mould so we know if it is current production or some long lost treasure.

Measurement tools and techniques are critical components here as well. The skill to use fine measuring tools also takes some time to develop.

Good luck on the quest! I know I can trust my measurements because I can repeat them consistently. Posting on the internet is anyone's guess!

[petroid]

I dont understand the need for any standardization. Not all alloys will drop the same from a given mold. Not all molds even with the same part number, especially Lee molds, drop the same with the same alloy. Not all casters get the same results from the same mold with the same alloy. There are too many variables to say this is always this no matter who or what or when or why. Just my $.02 Pete

[rsrocket1]

So why don't you just ensure your mold drops at least .358" and size them (or not)? I doubt you'll notice the difference between shooting 0.358" or 0.359" cast boolits so long as you aren't swaging them down below 0.358" in your loading process. My 0.358" mold drops all my boolits at least 0.358" so I don't bother sizing them. Just tumble lube, load, shoot.

[Cherokee]

I need my molds to drop at a minimum size for my guns, anything slightly larger is taken care of by the sizer. I always size/lube CB's. So, I note an average of doz or so boolits and if its more than my min, I'm good. With my shooting, I can't tell the difference and the gun is happy with no or slight trace of leading. I do clean them every 300-600 rounds, depending on the gun.

[243winxb]

Cast bullet diameters/weights are regulated by the manufacturer by the alloy they use. If you are not using there alloy, the diameter/weight as cast may be different. A higher percent of antimony will increase bullet diameter as it drops from the mould. Lee uses 10-1 lead/tin. http://leeprecision.net/support/index.php?/Knowledgebase/List/Index/13/product-support

[mdi]

The size dropped from a specific mold, for me anyway, will vary depending on the alloy used and the temperature cast. Higher antimony alloys tend to cast a bit larger, and even expand a tad after being cast. To answer your question, I would say +-.001 or more...depending.

Yep, me too. Different alloy, different finished diameter...

[cbrick]

billy boy, life would sure be a lot simpler if things were that cut & dried wouldn't they. For all of the reasons mentioned a chart listing such as cast diameters wouldn't be practicle or even useful. Plus you can toss in variations in casting rhythm, speed up and the mold gets hotter, slow down and it cools off so even with same alloy you'll have various diameters from the same mold/caster.

If your getting variations of .002" while using the same alloy it's not the mold, it's the caster. I have 70+ molds and without changing the alloy not a one of them have diameter variations like that. If I post that a given mold drops .358" diameter boolits that's what it drops, not .357" to .359". Even going to a high Sb alloy shouldn't increase casting diameter by .002" in a 357 boolit, possibly with high Sb in a .500" or larger boolit .002" could be possible.

Rick