Undersized Lee Mold Advice

I just got a Lee 405gr mold to start casting for 45/70.

I cleaned the mold and broke it in. I was able to get good bullets from it before very long.

However, the joy quickly faded when I put the micrometer on them. I'm measuring them at .4565 give or take a couple 10,000ths.

I was starting to doubt my mic so I measured some .45acp bullets to compare. The mic checked out there.

I bought a Lee .457 sizer with the intention of opening it up a couple thou. I tried the new .457 sizer, and the new boolits didn't give any resistance at all.

I've never had to call Lee before. Would they entertain a return? If they did, would I just get one cut with the same cherry?

I've lapped a Lee mold in the past as per the "Lee-menting" threads here to get it to work better. But I've never tried to hone out a couple thousandths before.

Any advice beside saving my pennies for an NOE mold?

What alloy are you using

45-70 bullets should be .458 minimum diameter!

If it's new send it back, if got it used get a refund and buy a new mold.

HM

I agree...send it back to LEE...I have that mold and mine drop at 0.459" with 2:1 - WW:Lino

redhawk

Yeah, alloy can make a big difference in "as cast" diameter.

Quote:

---

Originally Posted by 454PB

Yeah, alloy can make a big difference in "as cast" diameter.

---

Would it matter? Shouldn’t it drop at least 458 with any alloy? Maybe bigger with the ‘correct’ alloy? I’m asking, not debating. I always just mix all of my lead together. I haven’t ever cared what alloy I use cause I load everything slow.


Sent from my iPhone using Tapatalk

Lee might replace it but it may fall into specs then no. Different alloys may give more size also. Slightly hotter alloy and or mould may help do to expansion. Not smoking the mould may allow for another .001 - .002 on dia as the smoke adds to the blocks also.

I would lapp it if needed this wont be a real big job for .001 - .002.

Use several of those bullets you cast.
Drill a hole in the base that a piece of 1/8" key stock fits into and epoxy a 1 1/2" long piece into hole. drill hole as deep as possible with out breaking thru bullets front.
Make 2 maybe 3 lapps like this
Since this is an aluminum mould use finer abrasives. 600 grit if lapping compound is available or flitz, auto rubbing compound, toothpastes are slower but get the job done
Impregnate a lapp with compound by rolling it between to steel plates. lightly coat one plate with a small amount and spread then roll bullet with light to medium hand pressure.

Use a T handle tap wrench on the stem insert into one block and gently close on bullet. hold with tension on the handles and with a tapping motion make 3-4 back and forth rotations of 1/4-3/8 turn then rotate 1/4 turn repeating the back and forth do this thru 2-3 rotations clean and cast a few bullets to check size. Repeat to where bullet cast to desired size.
When lapping a hole or mould internal surface its 1 for 2, .0005 on a side is .001 on dia. Go slow and check often. depending on compound a little light oil or water will rejucvinate the compound and it will cut finer as it breaks down.

The alloy is a blend of range scrap. It's got a touch of tin and other trace elements, and is of moderate hardness. I could cast them of a harder alloy, but I couldn't see going much softer.

I did cast a bunch of 255gr for 45 Colt out of the same pot, and those were all right where they needed to be size wise.

I did buy some plated bullets to load as soon as my dies show up. Those will last me a while, so this might just stay on the back burner and I'll get an NOE or Mihec down the road.

I think I'll contact Lee to give them a heads up. If they want me to send it back, I guess I'll give them a chance to do their thing. If I get another one that casts the same size, then I can play with it.

Range scrap is usually low in antimony, which is what increases both hardness and diameter. If you can locate some type metal, it is high in antimony and takes a relatively small amount to increase as cast diameter. I have the same Lee mould you are using, and mine casts at .459" in wheel weight alloy, so it does sound like your mould is undersized. Adding 2 or 3 percent antimony could increase diameter by .001" to .002". Only you can decide which method of increasing diameter is best for you. Personally, since I also powder coat, I'd keep that mould and order another.

The Lee mold is 457-405-F
https://leeprecision.com/mold-dc-457-405-f.html
a boolit dropping at .4565 is only .0005 undersized, I'd expect Lee to say that is within spec.
You could try looking for another mold, but I suspect another Lee mold will drop about the same if you use the same alloy and same technique. You could try casting at a cooler temp with an alloy with more Antimony, but that may not be conducive for the caliber/application you want to shoot?

I think your own comment "saving my pennies for an NOE mold" is the real answer

If you're interested at all in powder coating, that could easily solve your problem too. A little lapping of the molds, and powder coating the bullets, and they'd be just about perfect. Powder coating alone would probably get them to .458" or better.

You could run them through your .454 sizer and paper patch them .