Remington's factory 300gr JHP moves at 1800fps. when sighted for 50 yards, it is 1.3" low at 100 yards.
It actually carries a lot more energy than the 405gr round.
I'm relatively new to 45-70, but some other members here have used the 300gr factory loads and had complete penetration on larger game.
I mis-understood the "more umph" part. as Bill stated, the big bore guys think more umph would be more energy, or getting the biggest piece of lead possible down range!
So far as your original recoil concerns... any of the factory loads are pretty mild. I shoot my Buffalo Classic with a lace on recoil pad I got at Cabela's for around 30 dollars.
This puts my felt recoil in line with my 12 gauge with birdshot. "Felt Recoil" is subjective, so as they say, "Individual results may vary".