I have read on other forums (oops) that a few, if not many users of this mold have had horrific results with accuracy. Now I don't know how much care any of these folks use when they cast, size, or load, so there may be many issues not mold related. One thing that did come out was that there maybe an issue with the version of this mold number. The Ideal version seemed to work for at least a few and the Lyman did not. This is not conclusive by any means.
I cast using an alloy that measures between 12 and 18 BHN with 14 being the mean. I have checked the hardness after 48 hours, 1 week, and 1 month. Why? Because lead hardens with age. I also do not measure on any part that has been worked, like a sprue cut. Why? Because working softens lead. My load development candidates are a month or more past their size/lube date, not the mold drop date, and they are sized 0.001 over bore. They are matched to 0.1 grain (relative) and do not show any base craters or bulges. I do this to try and eliminate as many variables as I can before I pull the trigger. Why do I relate all of this?...Re-read the top paragraph.
I have a couple of loads between 1200-1400 fps so far that print an inch or less at 25 feet with 70 year old eyes, and iron sights. A couple of tenths of a grain of powder around these loads are no good. I have rechecked the series and got similar results under differing conditions. The mold is an Ideal, single cavity, so there might be another data point in it's favor.
Does anyone else on here have any experience with this obsolete SWC mold?