My molds cast oval bullets

[chris in va]

Perhaps they are getting worn out, but my Lee 45 acp and 9mm molds cast slightly oval bullets. When sizing, the non-seam half gets squeezed the most while the seam doesnt even get touched half the time.

Any ideas why?

 

[Beagle333]

Do you have any tinning or buildup on the face of the blocks, especially where the lube grooves meet? Are the faces of the blocks completely clean?

Can you see any light between the mold halves when closed and held up to a good light?

 

[skizzums]

I have a mold that casts uneven bullets if I don't get the pins lined up just right, but oval I could only see if there was a burr or buildup SOMEWHERE on the face of the mold. Likely at the nose or in the pins. Only way it can create an oval shape is if its not closing all the way for some reason

 

[dahermit]

I have cast bullets since middle sixties with many different molds. I noticed early on that none of my molds dropped bullets that were perfectly round. However, most out-of-round bullets are less than .002 in. out of round and seem not to effect accuracy. Sweat it not, just use them.
The process of cutting a bullet-shape into an iron block, involves a spinning cherry, the is brought into contact with a solid block of metal. The cherry flexes resulting in a slightly oval bullet shape. Unless the out of roundness is extreme, there is no reason for concern. Nevertheless, one should look at the blocks while closed, against a strong light to detect blocks that are not closing properly.
It is notable that most casters are not aware that their bullets are not perfectly round because they actually have not measured them.

 

[reloader28]

I little out of round makes no difference really.
I agree, you could have a little bit of something between the mold halves.
It could also be a small bit of raised up area from something like where the sprue cutter goes across the top. Sometimes a bur will appear on the edge.

Check the alignment pins. Make sure they are in fully and solid. I've had to push them back in and secure them better on a couple the older style molds.

How do you close the mold? Make sure you set it down flat and close it gently. I use a 5"x5" piece of 1/4" thick metal. That keeps everything lined up better and the mold lasts MUCH longer.
NEVER slam a mold.

Also, put a tiny bit of lube on the alignment pins. Sometimes, just that will help.

 

[chris in va]

It's possible I have some buildup on the pins and mating surfaces. They get cleaned every couple sessions but I may need to use some non chlorinated brake cleaner or something to remove the lube residue.

If I squeeze the handles harder, you can tell the halves seal better.

 

[FrankenMauser]

Clean it up really well.
Remove any lead deposits that have snuck in, especially on the block faces and alignment pins.
Then check to see if the blocks have warped. (Straight edge. Thick piece of plate glass. Etc.)