Acceptable Out-of-Round

[hammer58]

I do not overthink this stuff.

That is probably the way to go. It would save a lot of grief, but I am really interested in the science of it all. Keeps my mind off of politics

[Ola]

I would bet OP is not a casting-robot, yet.

That'd explain the variation.

[Rattus58]

Generally speaking once you size your boolits they come back to round or certainly within allowable limits.

In my opinion, you should always invest in the sizer of the your bullets optimum diameter if available. As far as out of round goes, one of my most accurate 50 caliber muzzleloader molds is out of round because of my "tampering" with it but lo and behold, even as cast, they seem to "shape up" while underway... this is with damn near pure lead of course.. so I don't know if this works with an alloyed metal. A sizer certainly, in my opinion, should take care of any out of round issues... but I do have a question...

How is it that you have such disparity in your mold? I can see excessive shrinkage if it got too hot, but then you're usually down in the pot when that happens so add some lead if you can't adjust the heat would be my suggestion and it should cool down enough and cast a slightly larger bullet. There may be other remedies available to you...

Ok... after reading more of this... I see the problem with the sizing disparities...


Much Aloha... Tom

[kungfustyle]

If you go with a Lee sizer, check the boolits with a micrometer. I had to sand out three of my Lee sizing die so they were sized properly. Best bet is to get into a rhythm them with casting. Temperature plays a big role both with the pot and mold. Get a thermometer and find out the temperature of the melt you are using. My Lee pot with the dial set on 6 will vary from 700 to 800 degrees depending on how full the pot is. Get the mold up to casting frosted bullets, set it on a damp towel to cool it down and cast about three or four rounds of bullets, cool, repeat. See if that helps with the variation. Use the same alloy the whole casting session, make ingots ahead of time. Try to just cast and save the spru till you are ready to take a break. Let it come back up to temperature before you begin again. If you dump a pile of spru back into the melt that will cool things down to 600 or so. 100 degrees on the melt makes a big difference.

[toallmy]

That's a lot out of round , when you finish casting next time leave the last pore in the mold but cut the sprue . Then after cooling check the size out of each cavity ( it may show you something ) . That is assuming you have checked the mold out good to make shore the blocks are clean and aligned properly . Possibly just preheating the mold to a even temp could help . Over size out of round could be a few things , but under size out of round is that's a problem .

[Soundguy]

I don't weigh mine either. alloy in the pot probably changes slightly throughout the day as I'm casting and adding in more metal, so some slight variation is to be expected.

[Soundguy]

If you dump a pile of spru back into the melt that will cool things down to 600 or so. 100 degrees on the melt makes a big difference.

That's why I dump my spru pieces back in after each drop. easier to keep uniform pace, right amount of time for mold temp to stay in sweet spot, etc.

[MUSTANG]

Also, I weighed a random handful of them tonight on a Frankford Arsenal digital scale, and they all weighed between 233.0 and 234.0 grains. Is this normal weight variation?

That weight differential (range distribution) is good. It's only a 1/2% variation. For cast rifle boolits; I sort all of mine into groups with each group varied by 1/10th grain measured on a Frankford Arsenal digital scale. The truth is it is somewhat chasing a level of distinction that is flawed since the same boolit weighed - then reweighed a little later on that scale will fluctuate on the 1/10th scale reading; but overall I get better accuracy by doing so. For pistol/revolver I would consider it a waste of time.

[hammer58]

I would bet OP is not a casting-robot, yet.

No doubt about that

[hammer58]

If you go with a Lee sizer, check the boolits with a micrometer.

Ordered a sizer today from Titan. I also corrected the pin depth and cleaned the mold.

I'll report again when I have had a chance to run some more boolits.

Thanks everybody!!