is comparing the investment of $350 on a rifle(this is just the Ruger and not accounting for glass, ammo, or any accessories) vs how much training ~420 (or more) rounds of .270 would provide. A potential downside is .22 is very hard to find for reasonable prices. Personally I would value training time with the caliber I would hunt with over getting a different caliber rifle and having to acclimate back and forth. Your preference may vary and honestly range time with either beats range time with neither!
As for 1" groupings at the range not translating to 1" groupings for the hunt...a controlled and "sterile" environment like a public range is worlds away from being miles in the woods on rough terrain, poor target visibility, and having no benchrest to pamper your aim. A nice training drill I made for myself since I have a good amount of wooded land is have 50/100 yard target sheets and deer silhouettes placed in several areas. Treat them like a real deer (spot/stalk/position) and strive for that golden double lung shot. It really helped reduce my spoiled shots from getting in a hurry and/or adrenaline giving me shaky hands. Another trick is scouting and cultivating areas where you may hunt. Simple things like walking out and noting where the game activity levels are before the season begins, (gently) pruning a shooting lane where applicable, finding out if that awesome hunting spot you saw in the afternoon actually has the sun blinding in the morning, etc. The more you prepare the little things before you run out with a rifle means better and easier focus for taking the one shot that matters the most.
"Fortune favors the prepared mind." -Louis Pasteur