Yes, that is much bigger than a 45-70 shooting low powered rounds made for the questionable strength guns.Same here. Grew up hunting with a 12ga Remington 1100 as a kid shooting light field hybred exp. Those heavy slugs packed a huge punch on deer. I wish they were still available. That gun has a plastic butt too! My 30-06 with a sims is a piece of cake in comparison.
Now, shooting a metal crescent butt plate 45-90 with heavy smokeless loads... Yes that does hurt a little my more than my 12ga
When I first got my 458 win mag I bought a shooting vest with the padded shoulder and upper arm area. It could be worn under a coat for cold weather like Alaskan Brown Bear hunting. I max loaded 510 grain RNSP. Those rounds took out the African Big 5 on several loaners to friends safaris. They took videos of one shot DRT braining bull elephants. They were actually over kill on big bears.
When I was young I could shoot it maybe 20 times like at range and yes on more than one occasion it hurt me doing a quick shot and I would end up with a black and blue upper arm above my bicep. Sometimes things charge out of the scrub and you don't have time to set the rifle right! kinda like pheasant hunting with a 12 gauge and they jump up right in front of you. Startling you!
I've seen those rubber stock covers, maybe you should invest in one!