It does little good to recommend a caliber difficult to get ammo for, especially long range paper punchers with very few hunting loads. And, those hunting loads don't fly as flat, due to the different construction and purpose of the bullets.
Point blank range is the distance you zero at to get no more than 6" bullet drop. For most 30-30 loads, it's in the 250 yard range. After 350, bullet drop becomes significant, but can be compensated. What is more important is loss of energy. Once velocity drops under 1,200 to 1,800fps, expansion also becomes moot. Hunting bullets are designed to reliably expand only over a minimum threshold speed.
There's a lot more to it than which shoots flattest. Plus, most hunting takes place under 400 yards, and the majority of shots in woodland and edge generally are less than 180. At typical ranges, the .30-30 really is a laser beam, because it's still in the portion of it's ballistic curve where it's mass allows carrying enough energy to overcome it's drag, and there's no significant drop.
Under 400 yards, the real consideration is how much power you need, and smaller calibers do significantly well. They still carry enough power for medium game. A lot of hunters would actually be better off not using the heavier calibers over .308, because in use, they anticipate recoil and accuracy suffers. It's hard enough to spot game and sight in during the few seconds they are visible, no sense making things worse knowing recoil is going to smack you with 35 to 60 pounds of force. Getting a scope jammed in your forehead just once isn't forgotten.
In general, picking a caliber has tradeoffs. It has to fit the action you plan to shoot, and be available. The bigger the bullets diameter, the more power it can absorb, but the less aerodynamic it's shape when limited to the same overall cartridge length. Fat, short bullets can carry more initial power, long skinny bullets can carry it further, both have a limit where speed, expansion, and bullet drop are no longer effective.
Again, in general, and on medium game like whitetail or hogs, calibers under .30 and case lengths less than 50mm do ok. Going beyond either dimension puts it back in the "full power" category of significant recoil that can affect the shooter, and requires a larger, heavier gun.
If there is one thing hunters generally agree on, it's that rifles over 8 pounds need a significant reason to justify carrying them miles into the backwoods. Hence the popularity of the lever action, vs. military issue battle rifles. The latter are more likely to get shortened and restocked. It's exactly why they are no longer issue. They are too heavy and have too much recoil.
Avoid the magnums, pick a popular and effective intermediate caliber, and enjoy the day hunting.
