Vern Humphrey
Member
I don't know about the .243 but my father has a very old ruger M77 (from back when ruger outsourced barrels) in 6mm remington
The 6mm Remington started out as the .244 Remington, designed to go head-to-head against the .243 Winchester. It has a bit more zip than the .243 -- but not enough for a deer or prairie dog to notice.
Remington, however, specified a slow twist for this cartridge, so it would not handle the heavier bullets. The .243 Winchester therefore was the more versatile round, being able to handle longer, heavier bullets for deer, as well as being a great varmit cartridge.
Remington changed the twist and renamed the cartridge -- to avoid the stingma attached to the .244.
If you like the 6mm Remington, you'll like the .243 Winchester.