I have tried a few Lee moulds and they prove the old credo that you get what you pay for, spend the extra money and buy a quality mould that is made properly and works right the first time. As stated above I have aluminum block moulds from Mountain Molds, NEI and LBT and they are all high quality and produce excellent bullets. The latest Lee mould I tried for my 500 S&W is the worst one I ever bought, it overheats easily due to the marginal sized mould block for the size of the bullet and it is impossible to cast a round bullet with it. The two halves of the block will not align properly and I am not interested in trying to tune or align it mainly because I hate junk that doesn't work right. I have also been casting for many years and that last Lee mould is a disgrace to the company in my opinion. I know this sounds like a bit of a rant but I thought that I should share my experiences with Lee moulds since I have had different luck with them than the luck 10X above has.
Try turning down the temperature on your lead pot, An aluminum mold with cast good bullets using a lower alloy temperature than an iron mold.
Over heated aluminum blocks will be difficult to close as well.
If you can't get a Lee mold to cast a good bullet after following the instructions, send it back to Mr. Lee.
I have run three molds at a time when casting large diameter bullets.
two are always cooling while I'm dropping the bullet from the third and refilling it. It seems to take care of any overheating problems.
1) If your lee mold is over heating it will result in out of round bullets. I have a lee .577 mini mold that will overheat quickly. It takes about a minute to cast a bullet with cooling time. I have resorted to cooling the mold by puttng a wet towel in a shallow pan and resting the bottom of the mold on it while the bullet cools - and dipping the tip of the sprue plate into a pan of water to keep the blocks cool. I have a set of Lyman .577 mini blocks that over heat as well. Getting the iron lyman mold to cast a good bullet and NOT go out of alignment when hot is how I figured out the wet towel trick. That is the only Lee mold that I have had any real problem with.
I also turn down the pot temperature when the mold shows signs of overheating.
Try casting 577 bullets with a brass mold. That is a true challenge. You can get a not bad bullet out of a brass mold. Getting a consistent bullet with a brass mold is a leaning experience.
2) Lee molds can be returned to the factory if they don't cast a good bullet.
Generally I have found that the rules for using a Lee mold are a bit different. You can cast with a lower alloy temperature, You really do have to smoke the mold with a non waxy flame - it does make a difference.
A failure to lubricate the pins and sprue plate will cause "alignment problems".
So will a small bit of lead between the mold blocks.
I have yet to have a new Lee mold out of the box that didn't cast an acceptable bullet when I followed their instructions. I have bought used Lee molds that have had issues that were usually resolved by a thorough cleaning and smoking with a wooden match (wax free).
As for out of round my micrometer tells me there are very few bullet molds that cast close to round bullets. My shooting tells me that an oversize bullet that is slightly out of round doesn't seem to matter as much as having a sharp edge on the bullet base and sorting the bullets by weight. In 45/70 I also orient the bullets in the bore by using an index mark on the nose of the bullet ( an airvent cut .002 deeper on one block). This caused my groups to drop from 2 1/2 inches to about an inch at 100 meters - go figure.
The most problem with an aluminum block load is with an oil or varnish in the mold. It doesn't seem to burn off as quickly as with an iron mold.
If a lee mold casts a wrinkled bullet I clean it immediately in brake kleen, rince it with alcohol, air dry it, and smoke it.
When a Lee mold works well it works extremely well. When it doesn't work well, take a few minutes to clean it, get it warm, and lube the pins. Lee molds have also taught me how to cast better with iron molds.
For what it is worth I do have several lyman molds that I have purchased brand new that do not cast bullets that shoot accurately. I have a .225415 that is supposed to throw a 0.225" bullet but what comes out is 0.224 on the mold line, and 0.2235" at 90 degrees to the mold line. Bullets from this mold give pie plate groups at 100 metres from any gun. A used .225415 off of ebay that casts a bullet that is 0.2255" (cast line) by 0.225" (90 degrees off the cast line) will give groups that are under an inch.
My buddy has several custom molds for his 45/70. He was complaining about poor bullets and he had purchased several molds in succession because the molds were not giving him good bullets. I gave him 75 lb of pure cleaned lead and a 1/4 lb of clean tin. He was very pleased with all of the bullets cast from that alloy. I had trouble casting 314299 bullets from 5 lb of his alloy that he gave me. I remelted the cast bullets, fluxed and cleaned the alloy really well - as well as cleaning my lead pot and the second batch of bullets cast just fine. I suspect the problem was small solid particles suspended in the alloy that a second cleaning removed.
I have found that it doesn't take luck, it takes a clean alloy that is heated to the proper casting temperature, a clean mold that is properly smoked, and the patience to let the bullet cool in the mold before opening the blocks. Get the timing right and the bullet will usually drop from the mold blocks by gravity or a light tap on the handle hinge. Open too soon and the bullet may stick in one block ( or the other). You really know you are opening the mold too soon when the bullet sags or deforms as it is falling to the drop cloth or bucket of water. (I've used both)
Iron molds seem to dissipate heat faster and have a shorter cooling time.
I have a Lee mold that throws a 180 grain bullet and a very similar lyman mold that throws a 180 grain bullet. Bullets cast from both molds shoot to the same point of impact with the same load from the same gun. Groups from both bullets are under 2" at 100 metres. All being said you can't tell what mold cast the bullets by looking at them or shooting them.
Both molds cast well with a clean alloy - the lee heats up faster and gives good bullets sooner.
