.223 isn't the best choice for deer, even when legal. Often times it requires a head/neck shot to put them down, as the small bullet often times won't do the job in the 'boiler room'.
That said, it's legal here in NH, and with the right bullet, I'm thinking a Nosler Partition in 60 gr out of that faster twist barrel, it would make a nice rifle. I loaded some for my FS, and even with the 1:12 twist the accuracy was fine. If I ever decide to hunt deer, I would try it.