I ALWAYS bring a spare rifle chambered for a common cartridge when I'm going to hunt more than a few miles from home. Some years ago, I was hunting deer near Wray, Colorado, and saved a guy's hunt by loaning him my spare 30-06. He was from Ohio and discovered that he didn't bring his 6.5x55 ammo with him. IIRC, the closest dealer with 6.5x55 ammo was Cabela's in Sydney, Nebraska, a couple hundred miles round trip away. Anyways, I loaned him the S&W C and he punched his tag.
When my FIL was alive, we kept a Remington 710 in 30-06 around for deer camp for a couple of years. A couple of guys used it in lieu of their own rifles, either 'cause they were cheap and didn't want to shoot their own ammo or because their rifles weren't zeroed. In any case, having the spare rifle allowed them to punch tags.
