Can you tell us why you're considering .40 Open?
That would best lead to more focused answers like -
If you're starting from scratch, there are better options in the .355 bullet diameter.
If you've got 30,000 pieces of 40 brass, you might wanna consider 9X40.
If you just want cheap brass, go 9mm major.
If someone has a smokin deal on a nice looking 40 cal open gun, and you like it - get it.
If you already have a complete open top end in 40 and only need a bottom end, go for it.
etc.
what is 40x9? is that like .357sig?



























