Still having issues with Lee 310gr mold

[ghh3rd]

The continuing saga of my Lee 310gr mold. It may be all me, but I've been having a terrible time with it. My boolits come out a variety of sizes and roundness.

I just cast another batch last night, after modifying my process in an attempt to improve the boolits. This time I:
- Added 3% tin to the WW
- Water cooled them, so they wouldn't 'sag'.
- Attempted to cast cooler, although I wasn't getting good fill until my pot was set to 7.5 - 8

I added 13.4 oz of Babbit (unknown amount of Tin -- assumed 50%) to 14 lbs of WW in order to add
about 3% more tin.

Water dropped them so they wouldn't 'sag' out of round, as someone suggested.

I cast about 150 last night. A few were .428? :-( How could that be?

Many are oversized, dropping at various diamaters, such as 431, 431, 438, 429, 438, 430, 428, 429, 438, 436. On most, rotating the boolit in the calipers gives a wide range of measurement, up to .006 variance. I definetly don't have round boolits, although visually they look perfectly filled out.

If I measure the bands individually, I get various measurements along the same boolit.

I think that I will lap out my .430 sizing die to 431 or 432 and try using these bloated boolits, but that means having to measure all of my boolits to weed out the undersized ones :-(

I wonder if the gas checks will still get clamped onto the boolit if I lap my Lee push through to .432.

All I want from this mold is some decent 310gr to practice some 50 yd shooting, so I can get ready
to find a hog. I just put on my Ultradot, but that may not help me if I have wobbly boolits.

I still may send it back to Lee to check. Perhaps I should buy another one meanwhile?

Sorry for this novel

Randy

[pjh421]

Well Randy, the first thing I would do is indiscriminantly load and shoot all of them. You may discover that your gun does not care that they are not all the same and save yourself a lot of heartburn. What's a few primers and a little powder? Shoot some groups, check for excessive leading and record what you find out. You may indeed have to leement your mould but let's make sure there's a problem like 10" groups at 25 yards first.

Paul

[sagacious]

Pardon me for saying this, but if the problem lies with the pourer, sending the mold back will not effect a solution. Make sure you're doing everything 100% correctly first.

Are you saying you now have 6% tin in your melt? That's way too much. 3% is unquestionably more than adequate for your application.

Are you holding/touching the sprue handle when pouring? That will result in precisely the wide range of diameters you report. This sounds like it may well be one of your problems, or perhaps be causing the whole problem.

Is the sprue plate screw overtightened? That can reduce venting, and cause poor fill-out (forcing you to crank up the heat to overcome this deficiency). It may also cause varying diameters.

Are you pouring too hot? Do not dismiss this question. Small as-cast diameters can result from overheating the melt. That is a large cavity mold-- high heat is not a prerequisite for large cavities.

Is your mold up to temp before pouring 'keepers'? Inadequate or inconsistent mold temps will often give varying as-cast diameters (mold temp will vary widely when you're pausing to scrutinize your work, or weed-out rejects). Do not vary or interrupt your casting pace.

Are you putting the cooled sprues back into the pot? That can cause melt temp fluctuations. Many folks crank up the heat to alleviate the temp fluctuations, but often that's only a partial solution.

Are you sure you need to water-quench? That can slow down or disrupt the pouring routine and cause mold temp fluctuations. You may be better-off getting the basics down with that particular mold before you get fancy with heat-treating. Remember that each mold is law unto itself.

Here's one thing we know for sure: Your mold is clearly not undersize, since you report oversize castings. In light of that fact, lapping the cavities seems like an unlikely fix for your problem. Even a half-way decent mold will not drop sizes all over the spectrum as you report..... but operator error will make a top-quality mold drop varying sizes. I think that needs to be your avenue of approach to this problem.

I have that same mold, and use clip-on ww lead plus about one-half percent added tin. Perfect pours are the norm, and since I don't cast at a unnecessarily high temp, the bullets are hard and don't 'slump' when they hit the folded towels and I can keep up a fast pouring pace.

I often size at .431" with that mold. Gas checks crimp on fine. .432" probably will as well, but you'll need to verify that with your setup. Attempting to size any castings over about .432" will not likely work very well at all with that bullet design, due to the wide meplat and long, shallowly-sloping shoulder. Better to correct the casting problems than to try to over-size the bullets.

There's a number of things that could be the problem, even beside the questions/points listed above. Eliminate each of those pitfalls, and see if the as-cast diameters don't settle down.

Hope this helps, keep us posted. :drinks:

[ghh3rd]

Thanks for all of the advice -- I shall be dumping all back into the pot and starting over again, tonight. I am looking forward to resolving this and getting my gun sighted in with these boolits.

Randy

[Freightman]

I have the 310gr 44 mould and the first casting was bad, shot hem anyhow out of a Vetterli 1881 shot 3" at 100 yds over there sights. The second batch was good, never figured what I did but it was me.

[Rick N Bama]

I have two , 2-cavity copies of this mold. One is "scalped" & casts a plain base boolit of around 265grs while the other is untouched except to do the general "leementing".

With both of my molds, I've found that cranking the Lee pot up to about an 8, then slowing down my casting some, while cooling it a bit with a damp rag, produces some really good boolits. I've not noticed a problem with either weight or out of roundness. Quite frankly I've not put the calipers to many of them, but of those I did check, I didn't see a problem with their size.

Give the damp rag method a try while casting hot, but slow. When mine gets to going, I get around 3 drops per minute. Not the fastest casting molds in the world, but why do we need speed? We're suppose to enjoy the casting, right:)

Rick

[yondering]

First, start with the basics. Get a casting thermometer; Surplus Center has a big selection of thermometers, I got mine for $15 plus shipping. They have an online catalog. Setting your pot dial to 7.5 or 8 tells you absolutely nothing. One of my pots holds 800 degrees at "7", another does the same at "4". Temperature can change dramatically with different lead levels in your pot, for the same dial setting. You're working in the dark without a thermometer.

Second, it looks like you aren't getting the mold closed all the way sometimes. Check for burrs around the alignment pins, and/or small bits of lead between the mold blocks.

Are you getting a specific shrunken spot on the side of the boolit? Is that spot frosted? A bunch of my Lee molds do this. Sometimes it's because the mold is too hot. You can run the melt pretty hot, but still keep the mold cool enough to avoid this, by several methods. One is to cast slow or use more than one mold at a time.

I sometimes keep a small dish of water next to me, and lightly dip the bottom of the mold in it for 1-2 seconds when I see the mold getting too hot. I'm sure somebody here will squeal about that, but I've been doing it with most of my aluminum molds for quite a while now with zero problems. It lets me cast a lot faster.

If you have a six cavity Lee mold, I've found the block with the sprue plate attached gets hotter than the other block, and the shrunken area of the boolits always happens on the sprue block. In this case, sometimes I'll cool off just that block in water, just enough to even out the temp again. With those big boolits and a hot melt you'll probably have to do this every 3-4 pours.

[jhrosier]

Lee moulds seem to like a tiny bit of lube on the alignment surfaces to help the blocks align properly.

Jack

[sagacious]

Thanks for all of the advice -- I shall be dumping all back into the pot and starting over again, tonight. I am looking forward to resolving this and getting my gun sighted in with these boolits.

Randy

Best of luck. I suspect that you'll find and resolve your problem very quickly. The extreme diameter variations you describe are such that the solution should be immediate and easy to effect when you identify the problem.

None of the suggested fixes I listed above are difficult or tricky. Don't do anything drastic until you've checked out the easy fixes. Just hang in there, be patient, and you'll get it straightened out.

[fredj338]

Lee moulds seem to like a tiny bit of lube on the alignment surfaces to help the blocks align properly.

Jack
It's actually a must. I have the same 2cav, they really are a ***, but wil cast decent bullets. I use ww & have no problem throwing accurate 308gr+/- bullets. I do size & seat GC, they work fine. I'm not sure water dropping is really req'd. Try air cooling. FWIW, I always cast w/ the sprue plate touching the pour spout.

[arcticbreeze]

Hello Randy

Have you by any chance tried casting with one cavity at a time and measuring to determine if the cavities are not cut the same?

[ghh3rd]

Hey Marc - no, but that's a good idea and I'll try that. It's probably me, but it's just frustrating. I've tried temperature, alloy, bottom pour, ladle pour, water drop, air cool, etc. Sagacious provided a lot of good information which I'll use, and as he said, "Just hang in there, be patient, and you'll get it straightened out."

On a more positive note, I opened my mail today and found the Lee TLC 430-265 RF 2-cavity mold that I ordered a few days ago. It's one of the RD 432-265 that Lee cut at 430 by mistake and are selling off.

I just cast quite a few from the new mold, and they all measure 431.5 or 432 with the same alloy I've been trying to cast 310gr with, and these seem nice and even. A nice break from the struggle with the 310gr :-) I even popped a gas check on one and it was a nice snug fit but slid on evenly. Yahoo.

Now to figure out a good load -- I think I'll look up your post with your loads as a starting point.

Randy