John,Originally Posted by JohnH
All steels can warp. But what makes you think a $50 mold that is mostly labor has been stress relieved? Even if the origional steel has been, the speed at which and the cutting process itself can induce stress that will cause it to warp again at some point. That's why most molds need adjusted after they are "broken in". The larger the bullet diameter and length, the more likely the remaining material is to warp. And the larger the warp will actually be.
After the first couple of heat / cooling cycles "ALL" molds .... shift. That's why it is so hard to guarentee roundness. Mis-adjust your pins, and you lose roundness. Beagle, and you lose roundness. Choose to do nothing and ignore warpage movement, don't adjust your pins, and you've lost it.
Kinda damned if you do, ........ type of thing. This is why I always have my molds cut larger than I need by .002 or more. This covers most minor warpage or shrinkage problems, allowing me to correct it by sizing.
This is a reason I like brass molds. It doesn't seem to warp as readily. If brass is going to warp, it does so when the cavities are being cut. Then that is on the maker, not me. He will probably try to use that set of blocks for a larger / longer bullet on another order that is large enough to clean up the warpage. But sometimes it just keeps walking too. Still, when you get a good brass mold, you got a good mold for a long time assuming you take care of it.