What do you want to use it for?
If you intend to shoot it occasionally, by all means join the "mine's bigger than yours club" and buy a 45-110. You will feel ever so macho as you develop a world class flinch and risk detached retinas. Yes, you could down load it to 45-70 potential, if that makes any sense to you instead of buying a rifle in that calibre to begin with.
Shiloh will dissuade a customer from ordering the Tom Selleck "Quigley" model, recommending a chambering less punishing. Guys that do a LOT of BPCR Silhouette shooting (like Mike Venturino, Steve Garbe, Dave Gullo, et al) tend to favour the 45-70 and 45-90, but then, what the hell do they know?
I'm a casual BPCR shooter, but when I hit the range with one of my Shiloh 45-70s, I put 40-50 rds down range in a session with no ill effects. Works for me ....
My favourite BPCR is a Shiloh carbine chambered in 50-70. The same amount of powder and lead that would rattle your teeth in a light carbine like a 45-70 Trapdoor is a pussy cat to shoot in a 50-70 carbine. Bigger bore = less pressure. Drops large black bears like lightning.
A pal has a Shiloh 'Business Rifle' chambered in .50 Alaskan. Only performs well with a 600 gr bullet and top loaded with BP. He misses very well with it out to 200m. I've spotted for him several times and he is flinching before he has finished the course of fire.
He has a top of the line Shiloh on order chambered in 45-70. You pays you money - you takes you choice ....