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View Full Version : Getting inconsistent bullet weights from my lee molds



chutestrate
02-27-2011, 06:48 PM
I'm casting for 175 gr 40 cal bullets. I randomly weighed 12, and I am getting 180 gr, 186 gr, 184 gr, etc.

I'm using a dillon scale non-digital to get my weights.

Should I just use load data for 175 gr for loading even with the different weights?

RobS
02-27-2011, 06:57 PM
How many cavities? If a six cavity then once heated up drop six in order a few different times so you can compare from a few samples.

Also is your fillout good on all the boolits i.e. sharp drive band edges and sharp bases on the bullets?

Wrbjr
02-27-2011, 07:02 PM
Ditto, I have that mold but have not used it yet.
I have used the 124 grain 9 mm. It measures from 126 up to 131 grains so I am in the same boat so to speak.
Seems like a lot of variation. I guess the alloys we use can alter the final weight from Lee's designation. However you would think the lot would be consistent, right? Interested to see responses from some experienced casters on this subject.

fryboy
02-27-2011, 07:02 PM
i have this mold in a two cavity ( you didnt state how many in yours ) variations can and do occur in different cavities , that much is normal , mostly with mine they average 178 grains using my #2 alloy and about 180 using a softer higher lead percentage alloy , again this is normal IMHO , while it usually is safe to use data for a heavier bullet/boolit the reverse isnt true , it is also possible that tension when clamping the two cavities together or a speck of lead or such holding them slightly ( even if preceptively noticeable ) apart can cause variations , i would suggest mic'ing them and if one caity or more is out of spec either return the mold or mark the cavity in such a way that one could then sort easier

x101airborne
02-27-2011, 07:30 PM
I fought and fought and fought this in my lee molds. Several of them would vary 2-3 grains +/- from cavity one thru cavity six. I troubled with this and finally found a solution. And thru all my trials and errors, the solution was incredibly simple... Ya ready?..... You sure?..... Here it is!



Stop buying lee molds and order a Mihec or other quality controlled mold. Doesn't matter from whom. Put it to you like this..... Order one to replace this lee. Run it for a while. Do weight measurements. Do concentricity tests. See how easily they drop from the mold. If your accuracy doesn't improve, your frustrations dont go down, and you dont make bullets better than ever with fewer rejects, I'll pay you what you paid new to buy it off of you. I am that confident. I understand that molds get expensive and we are all trying to do this on the cheap / under SWMBO's nose, but I would rather have and love one mold in each caliber / application I use than have a shelf full of poorly made molds that I still dont like or cant use.

chutestrate
02-27-2011, 08:18 PM
I'm using a 6 cavity mold. The fillout is great. Good sharp edges.

So using load data for 175 gr bullets is ok for these heavier slugs?

RobS
02-27-2011, 08:21 PM
You'll be fine with the load data just start at the minimum and work up. It sounds like the mold cavities are a bit different. Measuring the boolit diameters may give you an answer as the fatter ones or possibly longer ones will likely weigh more. I would also make sure the mold halves are closing completely. Simply close the mold, put it up to the light and open up the sprue plate. You should see no light or a very small amount between the halves which should be even from one side to the other.

Shiloh
02-27-2011, 08:25 PM
That mold is good for me. After LEE menting the mold, it dropped perfect consistent boolits.
It has since had the bevel base trimmed off, and now drops perfect 158 or so boolits.

Shiloh

oso
02-27-2011, 08:50 PM
Mold closing completely each pour?
Mold and alloy up to consistent working temperature?
Alloy clean and free of inclusions?
Boolits without no wrinkles or voids, no torn or bumpy bases?
Then mark each base after you cut the sprue so you know which cavity the boolit came from, check for out of round when you weigh. If a cavity is off spec I would expect it to be consistently off spec.
If so, call Lee, they did replace a mold for me with such a problem.

10x
02-27-2011, 09:14 PM
Are you leaving enough sprue so that the bullet can fill as it cools?
And is your alloy hot enough?
Does it do this after the mold has heated up?

Also do what oso says.

I have had very few problems with a lee mold that were not caused by me or ages of abuse (used molds from gun shows) and I have dozens and have used them since the early 1970s.