Vanbuzen, again, no offence taken, but you may want to spend a weekend watching the local NRA high-power guys make 8" groups out of TEN rounds at 300, RAPID FIRE, sitting on their butts.
300 yards IS a long shot, and because of my failing eyes, would never try one anymore, but it's certainly not out of the reach of many shooters, and IF one has practice at that range, and IF one is comfortable trying that range, a lot of lever calibers are plenty capable of doing the job.
Case in point is the .38-55/ .375 Winchester. 100 years ago, no one told those guys their .38-55 wouldn't work at that range. Imagine their surprise, when as old men they read in the magazines of the early '50's that lever guns were worthless beyond 110 yds.
I sure wouldn't want to be on the wrong end of even a .30-30 at 300.