Casting from new Lee mold

[Boolit_Head]

I cast some from a new Lee 452-230TC mold and as one would expect it measured a thou oversize nicely. Turned the slug 90 degrees and measured about 2 thou undersize. Could this be a temp issue? The slug was nicely filled out and appeared to cast well.

[williamwaco]

Which was the largest? Across the joint of perpendicular to the joint?

[Boolit_Head]

Good question, I'll have to sit down tonight and do some more measuring.

[williamwaco]

If it is larger perpendicular to the joint, you may have something holding the mold blocks apart.

PS: It will never be perfectly round unless you know how to do a very careful job of lapping.
Even then the roundest mold I have ever seen is still out by half a thousandths.
Most are out by one to two thousandths.

[Boolit_Head]

Checked that nothing holding it apart as soon as I noticed the difference. Not to concerned about being out to far except these are undersize. No amount of running through the lubrisizer will fix that.

[Kraschenbirn]

My experience with out-of-round Lee moulds has been that they're usually fatter through the parting lines. If that's true in your case, you've got three options: (1) send the mould back for replacement under warranty. (2) Lap the cavities. (3) 'Beagle' the mould and let your lubrisizer true 'em up. Personally, I'd probably lap the cavities out to .453-.454 and be done with it...but, on the other hand, I've lapped/polished almost every aluminum mould that I own so it's not a major project for me, either. If you need some help, shoot me a PM and I'll walk you through the process.

Bill

[upnorthwis]

I would shoot them first, before I became overly concerned.

[shoot-n-lead]

I would shoot them first, before I became overly concerned.

X 2

I have them like this and they still shoot better than I can.

I am only speaking for me, but I learned years ago that looking for boogers in my cast boolits usually serves little purpose unless a problem manifests itself in the shooting and I have to go looking.

[bangerjim]

That is why we run them thru sizing dies. That will take care of most of any minor out of round you will have.

banger

[Boolit_Head]

Well in this case the sizing die is not going to add 4 to 5 thou to the width of the slug. About ever so slightly to the left of the parting line across the bullet measures .448 turn it a few more degrees and it measures .454 to .452 the rest of the way. I ran a few through the sizer and still undersized, Shootable but undersized.

[1johnlb]

Do they have good form, meaning are all the grooves filled out completely? I find on my first cast with any mold, I've got to clean and prep twice to achieve complete fill out of the mold. A little oil in one spot can cause what your complaining about and that oil is almost impossible to see. If you smoke it, where ever oil is , it will show up shiny.

[Boolit_Head]

Yes I scrubbed them then smoked them and they looked good. Going to try another casting session with them tomorrow. Tried a new NOE hollow point mold I got today and the bases came out perfectly round. Had a hard time getting the noses filled out though. I must have to cast hotter with them as I was casting with the lead at 725. My previous settings I used for the Lee mold must have been closer to 800.

[1johnlb]

Preheat that NOE to 300~350deg. and box the Lee back up you won't need it anymore. 700~725 is perfect, as far as I'm concerned. My 30 cal rg 2cav cast perfectly there. NOE has lots of tips on their forum.

[44man]

A round cavity is no longer round if too hot. It will be smaller 90* to the block sides so the parting line will be the largest measurement.
I found this making my own molds. I use a cherry and if I drop the cherry in a hot mold, work fast, I will remove a lot of metal and get a round boolit.
The cavity is not a hole in a piece of metal that expands from center, It is half a hole on an edge so the metal expands towards the edge. The parting line moves away from center.
If you could measure a cold mold, you would find it is perfectly round.
The hotter the mold and the more frosted boolits get, the smaller it will be 90* from the parting line.

[44man]

Lapping a mold is tough because of a lead-lag at edges with abrasives. Same as lapping a sprue plate that can turn it into a rocking chair. Edges cut faster then the centers. Only an end mill will give me a flat plate.

[sandman228]

Im having the same problem with a few lee molds I tried to make some .358 swc bullets about a month ago they were dropping in the .360 range which is great in my opinion but when turned in the caliper a half turn they were only .355 . now about a week ago I tried to cast some 200 gr .452 swc bullets they were dropping .435 then when turned a half turn they were only .450 . neither of them were brand new molds though .

[leadhead]

I just sent back two Lee molds with the same problem 358-125RF.
I really wanted this bullet, but am very reluctant to buy another.
Don't know if the 6 cav's are truer in roundness or not.
Denny