Here are some facts from the article I linked above by Paco Kelly, and you can see that a 275 grain .45 Colt bullet from a 92 action at 2,000 fps is way more gun than a .30-30 and will keep going past 100 yards:
"A better comparison indicator for me, of where a handloaded round is in the scale of killing ability...is to compare it’s standing against other rounds without the over rated muzzle energy figures. If you multiply the velocity times the bullet weight, and then divide by 7000 (number of grains in a lb, it’s the old Keith method) you get a better picture of actual power/killing levels compared to other rounds. 2000 X 275 div 7000 = KS(Killing Scale) of 79 for this 45 long Colt load from the Rossi 1892. A 44 magnum Ruger revolver with a 275 grain (same nose shape) cast WFN bullet at 1400 FPS velocity reaches a level of KS 55, and that’s a heavy handgun load that’s harvests larger medium game very well.
A 30-30 with a 170 gr bullet at 2200 FPS gives a level of power ranking at KS 53.4... ahh yes dear reader, the 44 mag from a long gun really does have more power at 100 yards than a 30-30/170 commercial load. Of course the 44 mag/275 gr. load above from a rifle, at basically the same velocity as the 275 gr./45 long Colt from a rifle has the same killing level potential as the 45 long Colt. There are difficulties with all measuring methods of bullet energy and killing ability since so much more is involved than just velocity and weight...but this works for me when we are comparing the same bullet shape/content and construct with changes in weight or velocity.
The neat thing about this method is you can take the down range velocities all the way out to your longest range and compare them with the down range velocities of other rounds, calibers and see the changes compared to each other. The 45 long Colt at 100 yards has slowed to 1600 FPS and the killing level has dropped to almost KS of 63 from 79. Where the 30-30 load has dropped to 1930FPS to a KS 46 from 53.4.....that should make a few yell ‘foul...can’t be’, but it is! And from my use of these 45 loads in the field for years on large game....I can tell you it is.....! As many gunwriters have stated over the years, a 44 mag or heavy loaded 45 long Colt fired from a rifle is more powerful than a 30-30 at 100 yards....actually they are more powerful than the great 30-30, at a lot further than 100 yards.....
So the next time someone states the 44 mag and 45 long Colt from rifles only has an advantage over the 30-30 under 100 yards...show him the error of his reality. But remember bullet drop with the larger calibers, is more than the 308 calibers ....But that never bothered me....mainly because I started rifle shooting without scopes and learned how to compensate....scopes were far from being seen, much less using them, when we were boys. (Some like to say so was smokeless powder, but I’m not that old).
Pushing a 335 grain cast WFN at 1800 fps is around top end for a 1892 action for me. That puts the KS at almost 86! So this gives a good picture of what a so called lowly 45 long Colt can really do. What a lion killer that 335 grain 45 long Colt load would be. The Win 94s and Marlins in 45 long Colt can push a 330 to 340 grain cast bullet to 1600 FPS and a KS of 76 and that’s no sleaze...because 40+ caliber bullets of this weight will penetrate incredible distances thru animals, with great disruptive force to tissue and bone. Except for upper bullet weight limit, because of bullet length and the less powder room in the 44 mag case and the 45 case....I see little difference in both up to 300+ grains. As long as shape, material of the bullet construction, and the velocity are the same. The slight differences in B.C. (Bullet Coefficient) make little down range differences between the two. Going to bullet weights of 325+grains and higher, begin the power level changes in favor of the 45 over the 44 mag...but as said is that potential power really needed in normal hunting in the lower states...Alaska yes, Africa fine...and it’s nice to have the potential if needed."