For anyone that "pays attention" while shooting and hunting, the 45/70 becomes in short order a very efficient and capable caliber. This holds true whether you limit yourself to its blackpowder capabilities or add intrepidity through a Marlin 1895 or Ruger #1/#3. It is a bad critter stopper with few equals, and a game taker extraordinaire. Taking a statement from Paul Matthews' book title--"Forty Years With The 45/70"--like him, my nearly 40 years with the caliber has only enhanced my fondness for the big ol' round.
I dabbled with ballistic extension of the sort that Brad spoke of. I had a Ruger #1 in 45/70 for quite some time, and like most folks that reload for and own a 45/70 that can stretch the caliber's legs a bit......I ran a few bullet types through it that could extract more from the caliber than Springfield Arsenal originally intended. Hornady 350 grainers to about 2100 FPS provided all the recreation any recoil addict could wish for in a 7-1/4# rifle; I am fairly certain that my shoulder blades collided repeatedly. I was most thankful that said bullets came 50 to the box--at that, it took 3 range trips to empty those monsters out.
90% of my 45/70 shooting gets done with 30.0 grains of IMR-4198 or Reloder-7 these days. I use a 385 grain FN/GC by Accurate or the Lee 405 grain flat RN plain base in a Marlin 1895. These clock about 1350 FPS, and aren't bad at all. With the oncoming ban of lead bullets for hunting in CA, the work with a "stopper" load for the 45/70 will commence soon with something of the proper unleaded flavor to keep the fauna freddies happy.
