Does this make sence?

[cdngunner]

So i noticed my bullets were a wee bit out of round and did not have enough friction in the sizing die to properly seat my gas checks. I decided that I would lap my mold. I used compound for polishing up car light lenses.

I went through the process three times using three bullets every time. My micrometer shows that my bullets are now o.ooo5 out of round. Great, right?

Here is the kicker. The bullets seem to not get bigger and actually slide through the sizing die easier.

So here is what I think has happened. There must have been a burr on the mold that I was not able to see. The polishing got rid of this burr improving concenticity. The burr removed made the mold smaller which was canceled out by the polishing I did.

What do you think? Do my presumptions sound reasonable?

[RickinTN]

Polishing compound probably isn't removing enough material. I used valve lapping compound on the Lee molds that I have opened up and it will cut enough material to get the job done. Polishing compound does exactly that....polishes.
Rick

[runfiverun]

if you had a burr that was removed you would have known it by a boolit hanging up on that burr in that cavity.
if the burr was holding the mold open the polishing would not have made it go away as you didn't work on the face of the mold halves.

[JSnover]

How much out-of-round were they to begin with?
Maybe the mold was just a little bit sticky for whatever reason, and your polishing didn't actually remove anything, but it worked the blocks enough to break them in.
i dunno, just a guess...

[TXGunNut]

Now all you need is a smaller sizing die or a Lyman 4500 to seat the checks.

[cdngunner]

Polishing compound probably isn't removing enough material. I used valve lapping compound on the Lee molds that I have opened up and it will cut enough material to get the job done. Polishing compound does exactly that....polishes.
Rick

Well this stuff is not like the proper polishing compounds that you would use on a buffing wheel, it certainly is not as fine as any of the stuff I have. It probably is about the same grittiness as comet.

the bullets were probably 0.0015 out of round. When i pushed them through the sizing dies, it locked like only one side got sized. Now when I push them through you can see the sizing marks all the way around on the bands.

hmmmmm????????

[JSnover]

the bullets were probably 0.0015 out of round. When i pushed them through the sizing dies, it locked like only one side got sized. Now when I push them through you can see the sizing marks all the way around on the bands.

hmmmmm????????
Good. So now you just want them to drop a hair larger to get a good crimp on the GC. Try a hotter casting temp, your problems might be solved.

[Larry Gibson]

What alloy were you casting the out of round bullets with?

Larry Gibson

[cdngunner]

WW plus 3%