Lee 2 cavity mold

[KenH]

Hello all - all my new molds are Lee molds, mostly 2 cavity. I've been having problems with the mold not casting the same weight bullets all the time, finally checked and it's either the front or rear cavity that's light, sometimes only a couple of grains, but worse mold had around 4 grains difference. Is this common for Lee molds? Do NOE, or other "high dollar" molds cast the same weight bullet in both (or more) cavities?

I took a bullet and polished out the light cavity and got a couple of the molds within <1 grain of each other. Now they're not the same diameter, but this should be taken care of in sizing after powder coating.

I'm wondering what other folks experience with multi cavity molds are. I've got an old Lyman 358156 dual cavity mold I've had since the '70s and it's <1 grain difference.

Comments?

Ken H>

[Tackleberry41]

You will learn like most, its just the way Lee molds are. Switch to NOE and you will say oh thats how they are supposed to work.

[Rcmaveric]

Your disparity of weight difference is more likely caused by uneven heating. Polishing out the cavities is one way.

Personally, I dont weight and sort bullets. I dont shoot past 200 yards and havent felt the need. My groups are satisfactory.

For different name brands. I feel my NOE drops more consistent bullets. That big steel sprue takes a while to heat, but it holds the heat better so the blocks do fluctuate.

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[Harter66]

Knock on wood ........
I have several 6C Lee moulds for pistols and they typically cast .5-7 under to 1.0 over . The 358-158 RF casts .3598-touching .360 and round to .001 with weight dispersion light to heavy more reflecting the pot level that a mould issue . The 6C 40 and 45 moulds throw 3-5 different weights but are close enough about .5 separation with an over/under of mean of 1.7 .....the 452-255 RF drops 263-265 gr .......so much for a 255 gr mould . The 200 gr sister mould runs 201-203 . Last the 401-175 runs 403-177.5-178.3 . All about plus 2 to minus 1 over the pot duration .

NOE version of the 454424 for 5 cavities shows 1 light at 249.5 and 1 heavy at 250.3 with the other 3 at 250.1 .
I've run 2 short runs in an H&G #130 for 7 @ 196 gr and 1 at 195.6 ..... I suspect the sprue hinge cavity ......
Mountain Molds O/U .05 for 200 , 453-350s in a 2 C .
M-P ......if the operator gets the PB pins in right ...... This 462-425 drops a 2 gr difference but that should close with the pins oriented the same in both cavities . In any case 5gr is hardly a concern in a 417 gr bullet with a .280 BC .
I have a 4c Lyman 257312 it runs 99.8-100.3 .

Technique is a factor in getting even pours and consistent weight . Every mould has its own quirks . Like airplanes moulds are mass produced one at a time by hand . Before lapping you might have tried reversing the pour order keeping the opposite cavity hotter/cooler or not over pouring the sprue hinge . Every mould that drops a small or under weight bullet for me does it on the off sprue hinge end except the ones the do it on the hinge end .

Just keep in mind 1% is the cup and core target limit and .3% is acceptable for premium bullets . Anytime you're pouring within 1% of mean mould weight you're pouring more accurately than factory form dies for cheap bullets are producing per 25,000 lots . That's 1 gr on a 100 gr varmint bullet , and 5gr on a long range 45 cal target bullet , 1-3 gr on the typical pistol bullet .

[tazman]

I don't currently cast for rifle so cannot comment on those.
For handgun, I don't worry about a couple of grains here or there. Changes in my allow would more than account for those. I only watch for good fillout and no wrinkles.
Anything I cast is going to be as accurate as I am.

[Grmps]

I've seen many of the newer Lyman 4 cavity molds that were over 5 grains off between the cavities. I no longer buy new Lyman

If they are different weights they usually are different diameters.

If the molds are new and even after it has fully warmed up you still get different diameters/weights, I'd send them back.

I like buying from Amazon because they pay return shipping on defective items

[KenH]

Thanks to all for responses and they pretty much agree with my experience and thinking. I cast LOTS of bullets back in the '70s for 30 cal and .357 calibers. Most of my casting was with single cavity molds and only 1 or 2 dual cavity, and only 1 big heavy steel Lyman wadcutter 358 91 mold. I don't have a clue how close those 4 cavities are - I need to cast up a few just to check.

While I do agree 4 grains on a 400+ grain bullet isn't going to make a hill of beans difference in shooting out to 100 yds, I just like for them to be closer. ±1 grain would be ok, that's a 2 grain spread. I've got the Lee 457-405-F mold casting ±.75 grains and the 379-250-RF around ±1/2 grain so am pretty content with those numbers.

I should have mentioned I'm using a PID controlled Lee 20 lb bottom pour pot and do try for a consistent pour from pour to pour and front to back as a normal. I've tried back to front a few times, no major difference, but have not tried it on ALL my molds.

Thanks again to all for comments.

Ken H>

[TaylorS]

Most of my mounds are Lee’s and I’ve noticed a fairly large gap between weights I’ve not had any come under advertised weight most are 2-4gr over what the box says but,for instance my 356-125-2R will drop from 126-129gr I usually cull the lightest and the heaviest and save the middle batch for shootin


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[RED BEAR]

i personally would not give 4 grains another thought. i stopped weighing my cast bullets. i shoot mostly pistols and only to 50 yards as i can't see more than that. really past 25 yards is touch and go. if you are looking to go to a quality mold i will suggest a mp mold they are the best i have used.

[Taterhead]

I've had only one experience with a Lee 2 cavity, so take my remarks as anecdotal... It is my poorest performing mold, easily. Going from it to, say an RCBS 2 cavity is plain silly in how differently they cast. I have another buddy that has probably 10 2 cavity Lee molds, and most do fine for him. Though he does have some frustration with a couple, I believe. Plenty on this site have great success.

I look to NOE, Accurate, LBT or RCBS. They've all been very consistent. The real surprise to me is the quality of RCBS, being that they are a "production" mold. My 38-150-SWC is one of my favorites.

Of course, my one and only set of Lee Commercial handles had the handles come off the first session. Not trying to bag on Lee, but we just haven't started off on the right foot early in my casting career.

Lee 6 cavity molds are of much better quality, and NOE handles fit!

[KenH]

Lee 6 cavity molds are of much better quality, and NOE handles fit!

Interesting - you'd think they'd all be cut with the same cherry and have the same quality as the 2 cavity molds.

[RED BEAR]

i have had really good luck with lee molds all 2 cavity probably have 20 or so.

[MT Gianni]

http://www.castpics.net/subsite2/Classics/Lapping%20301%20by%20Oldfeller.pdf
http://www.castpics.net/subsite2/MoldMods/Fixing%20Lee%20Molds.pdf
Here are a couple of old ideas.

[KenH]

Yep, those are good pdf files on "tuning" up a Lee (or any) mold. I've done most everything mentioned EXCEPT the vent lines. I need to double check those because I've got one Lee mold that simply won't cast an non-wrinkled bullet. When the mold is up to temperature with hot lead, isn't wrinkles a sign of poor venting? I don't have a probe inserted in the mold, but when the puddle takes a moment to solidify the mold should be up to temperature, and this mold will still have wrinkles in almost every cast bullet.