My rifle certainly seems to like it. With it's huge BP firing pin, there has never been any trouble with pressure.
Benchmark in 48.0gr. load behind the 405gr. RP jacketed flat point produced 1,850fps in my rifle. As my rifle has a 3/8" leade or freebore, it loads as a normal .45/70, for overall length, thus I crimp in the bottom groove with a modified Lee factory crimp tool. I had to modify it as my case is only 1.9" long.

My long time but now passed away buddy Brad was on the scope watching. I had a Soule tang sight and globed aperture on the front. 10 consecutive shots off bags at 100 meters went 7/8" with the 405's and Benchmark. Incredible group, just an almost round hole 1.3" across.

Admittedly, I cannot see as well today, as I did those 6 years ago, but the rifle does shoot well still, with either sets of sights.

Benchmark, good load. Hodgdon's lists that 48.0gr. load in the max. column for low strength .45/70's with cast 405's at 1,695fps and 22,600CUP. They also list other loads to 28,000CUP, but not with cast bullets. The highest pressure listed with cast bullets are a couple load with 300gr. cast producing 24,700 and 24,900CUP using IMR3031 and Benchmark- making mid 1,900fps from a 24" bl.

Those speeds about duplicate the .450 BPE, seems to me.