It takes trigger time for a hunter to be confident in his choice of calibre (for you Non-Yanks) I hunt (big game) with many different calibers (.243 Win to 45-70) and the more time I spend shooting those calibres the more confident I am in taking a shot at game at a self imposed maximum distance for each one. The best way for me to stay sharp is shooting the various ground dwelling rodents that populate Northwest Colorado with not only my dedicated varmint rifles (.222 rem, (3) .223's (all bolt guns) .243 and 25-06) but also my big game hunting rifles (.243 Win (again) 7mm Remington Magnum (sevumag for short) 30-06AI, 300RUM and 35 Whelen. The 45-70 (Marlin 1895CB) is not a rifle I take hunting often because I'm not that comfortable with it, but it has harvested a small mule deer buck . . . . . from my deck.
Being a reloader, each rifle has it's own load developed specifically for it with a specific "target" in mind as well as the smallest group possible. Even the 300RUM has been prairie dog shooting and is quite entertaining for the uninitiated in it's capabilities.
"Aw, c'mon now, you take a 300RUM shooting prairie dogs??!"
"Uh, yeah, how do you think I got the monicker "recoil junky"!!