My .300 Blackout Sig MCX.
I like the .30 caliber for all my tactical weapons. A Ruger Mini 30 preceded it.
A Ruger SR762 is my battle tactical for more power with the same bullet.
I like the .243 6mm for long range varmints so I have a Ruger Precision Rifle w/ 24" barrel. Also a Shaw custom bolt action in .243 for a gun I can actually carry in the field.
digiroc