New rifle build

[bruce moulds]

kevin,
have you considered the 40/72?
just use hornady 405 brass as is.
ideally the chamber would not have a 45 degree transition, preferably 7 or even 4 degrees.
the little bit of extra case length offers more options with grease wads, and more power for longer range shooting.
this cartridge has proven to work well at 1000 yds in 14 and faster twists with 1.5" or slightly longer bullets of low drag design, being competitive with 45 cals.
capacity seems similar to the 40/82 of a case droptubed full of powder.
keep safe,
bruce.