[Alaska444]

Not sure why folks don't think the 45-70 lacks penetration. Take a look at the Garrett Hammerhead in 540 gr.

540-gr SuperHardCast gas-checked Hammerhead at 1550-fps*

RECOMMENDED FOR USE ONLY IN MARLIN RIFLES BUILT SINCE 1998

Energy: 2880 ft/lbs: Taylor Knockout Value: 55; Meplat: .360”;
Chamber Pressure: 35,000-cup; Brinnell Hardness: 25;
Trajectory: +2” @ 50-yds, ZERO @ 120-YDS, -8.5@ 175-YDS
*All ballistic specs result from 22” barrels.

FIRST CHOICE for defense against heavy grizzly

Our 540-gr +P Hammerhead Ammo is the ideal choice for stopping heavy bears at close quarters or hunting them at short range. This Hammerhead bullet has a meplat (frontal flat) diameter of .360”, which is just one tenth of an inch less than bore diameter. With its tremendous weight to diameter ratio (sectional density) it provides end to end penetration on the heaviest of bears, with exit, and does tremendous damage per unit of penetration due to its extremely blunt front end. This load is carried exclusively by NOAA for protection against coastal grizzly attack. It is also carried by the National Marine Fisheries Service and the U.S. Geological Survey for protection from grizzly attack. For the specific task of stopping a grizzly charge, this ammo has no peer.

http://www.garrettcartridges.com/4570540tech.html