KSCHEVY,
The poster who wrote that the .243 Win will kill deer is absolutely correct.
I've had more than a few shoulder surgeries. They're only going to get worse until they're replaced. Hence, I can write from a position of knowledge vis-a-vis your predicament.
You don't need another rifle nor do you need a muzzle break. Have a good recoil pad fitted to your stock, and you'll be good to go.
One would have to stretch a whole lot to claim a cartridge better than a .270 Win for North American big game hunting. It will kill deer very dead. It will kill elk very dead. As long as you put a .270 Win bullet in big game oxygenated blood pumping equipment, it will kill everything just as dead as any mega-magnum. Shot placement kills big game, not caliber diameter.
Bad shoulder and all, I can shoot a Model 700 .270 Win with 130 grain bullets loaded with 60 grains of H-4831. I can shoot the same rifle with a max load of 150 grain Partitions and RL-22 powder. I did have a recoil pad installed on my rifle.
I'm applying for bull elk again this year. If I'm drawn, I'll be hunting with my Model 700 .270 Win. In fact, while I have more powerful rifles, the rest of my hunting from here on out will be with a .270 Win. And it has a 22" barrel on it.
BTW, my 43+ year-old Model 700 in .270 Win will shoot sub .5 MOA. And I load for hunting, not target shooting.
One of the two farthest shots I've made was with my 43+ year old Model 700 .270 Win. But I'd rather shoot at a hundred yards than farther.