I do believe the 30-30 is the more powerful round, all things considered. My Marlin 336 shoots a 170 grain bullet about 2150 fps, a 150 at 2250 fps. The 44 Magnum in a rifle gets about 300 to 400 fps more velocity than the same round in a revolver, and therefore is a very powerful round. In my 1894 Marlin, I push 240 lead or 240 JHP at 1700 to 1750 fps.
The recoil of my 44 Magnum Marlin was so objectionable, that I removed the factory hard plastic buttplate and installed a hard rubber version. I purchased this rifle new around 1982 at a local K Mart. Had the original microgroove barrel removed by Marlin and they installed a Ballard barrel around 2000.
Code:
M1894 Marlin Ballard Barrel
240 Speer JHP 22.0 grs 2400 CCI 500
21-Dec-01 T = 54 °F
Ave Vel =1747
Std Dev =21
ES =68
Low =1717
High =1785
N =7
240 Nosler JHP 24.0 grs W296 WLP Fed cases
23-Mar-05 T = 65° F
Ave Vel =1725
Std Dev =7
ES =21
Low =1715
High =1736
N =5
240 Nosler JHP 24.5 grs W296 WLP Fed cases
23-Mar-05T = 65° F
Ave Vel =1752
Std Dev =12
ES =28
Low =1735
High =1763
N =5
240 Nosler JHP 24.0 grs H110 WLP Midway cases
23-Mar-05 T = 65° F
Ave Vel =1710
Std Dev =3
ES =9
Low =1705
High =1714
N =5
240 Nosler JHP 24.5 grs H110 WLP Midway cases
23-Mar-05 T = 65° F
Ave Vel =1745
Std Dev =12
ES =45
Low =1723
High =1768
N =10
240 Rem JHP 24.0 grs H110 WLP Midway cases
23-Mar-05 T = 65° F
Ave Vel =1719
Std Dev =10
ES =29
Low =1705
High =1734
N =10
You can compare the rifle velocities with the same ammunition in a pistol. The rifle really does push the bullet faster.
S&W M629-4 5" Barrel
Code:
250 LSWC 22.0 grs 2400 Midway cases, Fed primers
1-Oct-95 T = 75 °F
Ave Vel = 1336
Std Dev = 39
ES = 108
Low = 1286
High = 1394
N = 6
240JHP R-P 24.0 grs H110 Midway cases WLP
9-Oct-05 T = 66 °F
Ave Vel =1228
Std Dev =21.47
ES =70.16
Low =1268
High =1197
N=22
the twist on the Marlin has limited me to 240 grain bullets. The twist is so slow that when I tried 290's, they tumbled. The 265 gr bullets were after my testing. I am satisfied that a 240 gr solid bullet in a 44 Magnum would do everything I would need it to do. But not on Elk, Bison, or dinosaurs, etc.
What I don't know is a lethality comparison between the two based on wound channels. For something tough, like a bear, I would believe penetration through and through is more important than expansion. For the reason that I would want to make sure the bear is bleeding out as fast as possible. Bears are rugged animals, top of the food chain in the USA after humans eliminated all the megafauna. Up close, 50 yard ish, I don't see any reason why a 30-30 won't shoot through a black bear. Ditto for the 44 Magnum. Having shot both the 30-30 rifle is heavier, its practical range is maybe 25 to 50 yards more. Both rounds drop like lead balloons past 100 yards.
If someone had data that the wound channels of either are so close that it is six of one, half a dozen of the other, I would go with the 44 Magnum because it carries ten rounds, while the 30-30 has six.