First "bigger" bore rifle I got was a Ruger M77 in .270. I have had it since 1976. If you are considering using it for white tail deer or similar size game 140s are about right. I started shooting with factory stiff in 150 and up. It was just too much recoil and what I tought was overkill. Well, that was my opinion. Later I started handloadading, ostly cause you could not find any ammo back then in less than 150 gr. As I progressed with my handloading experience, I found that the 130-140 gr. loads were more than adequate for that purpose. I now have rifles in calibers like the 7mm-08 that use that weight of bullet at moderate velocities and dfo just as well without all the extra blast from the longer case
If I was going the hunt moose or elk, probably something in the 180 or so + range. But there ain't no such animals in south Texas. And, I won't be going hunting any where there are either. So, I use the lighter bullets and keep the loading down. If you are usiong factory stuff, you can only use what they load/ So, ya may want to try some Remington, Federal, etc in your gun to see which ammo groups best. I try to keep all the rifles I have to 1 MOA or less at 100 yds. For hunting, that is probably more than necessary unless you are shooting at very long ranges and if the targets are really small. But for deer and such a guns shooting an inch and a half at 100 yds if probably adequate for deer out to several hundred yards.
Probably more info than ya wanted, but I really like the .270 for versitility. I can handload it down to 100 to 115 gr. bullets for performance like a .243 or more like a .25-06 for varmints. Or load it heavy for larger game. However, now I have rifles in those calibers, so I loaded each caliber in a specific range. Not hat it does me much good. I don't hunt much now.
I have looked pretty hard at the Ruber American rifles. Couldn't decide last years which caliber I might want to try. I have a couple of Remmy 700s in .243, my old Ruger and a Remmy 700 in .270, a Winch Mod. 70 Featherweight in 7-08, and a Winch. mod 670 in .30-06. Tried a couple of .25-06s, but they were not as versitile as the .270s. So, I might want to get an American, but in a caliber like .22-250 if they make one. I'll be looking at them again this year.