I had the time this evening to cast a few bullets up. What a nice mold. Had good boolits dropping within 3 castings. Cast 80 in all for samples. I started with half pot of wheelweight set at low setting, and managed .459 diameter (no5 on lee 4-20) then as the mold warmed up the smallest diameter was .458. Got everything a little too hot once, and smeared the sprue plate. I tried a higher temp setting and water dropped, and the resulting diameters were much the same. Nicely filled out bullets with no frosting. Next I tried the monotype at a low temp setting, and that resulted in .460 diameter bullets. Roundness was within a quarter of a thou, which was slightly better than the wheelweights, but either way I think they would work fine without sizing. The gas check shanks came out at a taper of .426 and .430
I think I may have lucked out with this mold. I wish Rcbs included an allen wrench with it, I spent 1/2 hour digging through my toolbox.
A good experience so far, and even better when the gas checks turn up. At least I now know that I have a wide range of alloy choices. I may run 2 molds at a time to give each a chance to cool abit.
454PB, thanks for the suggestion on the lee push through. I did order one with the checks, I think it was .457 dia, but it looks like I will take it out to .4855 or .459, which should seat the gaschecks.