The “as cast” weight shows 427 grains. When the gas check is installed and the bullets are all slathered up with the Lee Alox, they weigh 442 grains.

Odd. I wouldn't have expected that. I’d have expected them to weigh LESS than 405 grains as cast given that lead is supposed to weigh more than tin and silver solder. I don’t know for certain but I think silver solder doesn't contain much silver and is mostly tin?

Maybe the mold just throws bullets heavier than the name would indicate..... It is an RCBS model 45-405-FN mold #82053. I started to wonder about the scale so I have checked the fancy electronic scale and it is dead on using a reference weight kit... Thank heveans because it is my QC for powder charges and it just wouldn't do to have it read inaccurately.

An additional mention of the loaded cartridges: I seated the first bullet in the case and then dropped the round into the barrel set (removed from the action) to see if it would chamber. The first time it stuck out about an 8th of an inch so I pulled the cartridge out of the chamber and seated the bullet deeper after an eyeball estimated number of turns down on the seating stem. Tried again and there was barely a rim width away from seating, so a 1/2 turn more on the seating stem and the round chambered beautifullly. As a result, these bullets seat quite deep in the .450NE 3 1/4 case and rest just off the lands. The die set is Hornady.

In the past I’ve learned the hard way about seating depth and the camming capabilities or rather lack thereof in double rifles so for any new load, I check the seating depth and verify that the rounds will chamber simply using gravity.