Not a +P load. An example would be HSM Bear Load ammo, 430gr at 1801 fps muzzle speed -
"Firearms capable of shooting our 45-70 +P ammunition:
Marlin 1895
Ruger #1
Browning 1885 High Wall"
http://thehuntingshack.com/?page_id=25
Darn tooten that's not only a plus P load, but much too high pressure to have on the north American commercial market!
The early Springfield 45-70 Trapdoor rifles were deemed to be able to handle a load of about 1440 fps, with 405 grain bullets, so that was the load shown for them, even if the early loads were black powder loadings. No commercial load can legally be more than this.
The US Army had the Springfield Trapdoor as their official rifle for two years around 1800.
About 25 years ago the wife and I spent most of a week scratching and digging on the old Fort Mojave US Fort on the Colorado River in Arizona. We found a lot of 45-70 empties where they were changing over to smokeless powder. We have samples of the three types of primers they were experimenting with, before they settled on the standard push in primer as we know it today.
The Army also shortened the case a bit, called it the 45-60 and made it into a carbine for their cavalry. This was the rifle that wiped out old General Yellow Hair,(forget his name) and his Tenth Cavalry at the Little Bighorn River, after the Indian bow and arrow shooters finished off the American shooters and obtained the Trapdoor carbines, to complete the event.
As a point of interest here, some years ago they swept the entire battle ground of the hill of the Little Bighorn with metal detectors. They marked the position of every metal fragment they found, anallysed them and had them replaced on the battle ground, exactly where they were. Anyone walking over the battle ground, as we once were, is told if they bend over and touch the ground, they will be searched. Thus, you know that when you are walking on the battle ground, you are being watched by people with a high quality binocular!