Originally Posted By: howlingWhat kind of range is that caliber effective at?
"That caliber" is effective at whatever range the cartridge associated with it allows.
For example the 204 Ruger cartridge makes the 5mm/20 caliber bore diameter a long range combination. The 5MM Rem Mag cartridge, because of its much smaller size, is a fairly sort range (150 yards) rim fire set-up. Yet they are both 5MM/20 caliber cartridges.
One (the 204 Ruger) has a .204" bore diameter while the older 5MM RM was listed as a .2045" bore diameter. But you can shoot regular 20 caliber bullets designed for the 204 Ruger in the Remington rifles. Several places market and sell CF conversions for the rifles using 22 Hornet cases or machine made cartridge cases to make up a CF version of the 5MM RF cartridge.
I have a Steve Schroeder CF conversion on the removeable magazine Remington Model 591 rifle, and it makes for a nice short range plinker cartridge that can be reloaded. I shoot 20 caliber (.204") 32 grain Hornady V-Max bullets in mine over ~4.5 grains of powder...... The rifle shown above is the fixed tubular magazine Model 592 rifle.
-BCB