The 1 in 12" will do just fine.
I just sold a rechamber (not by me) standard 223 - 1 in 12" barrel that I had bought here on GBO a while back to BCALL a few weeks ago.
With factory ammo it was about a 1" to 1.25" shooter but was able to work up a load using 29gr IMR 4320 behind a HORNADY 52gr HP that was getting just under 3/4".
I still have an old 22 JET barrel that was rechambered to 225 that will shoot a lot better than the one I sold.
It is a fine round, right on the heals of the 22-250.
The only thing I will say is that almost all of the books say to use (I beleave-I don't have my books handy) IMR4064 powder.
The barrel I sold hated that powder!!!
I have 2 Win model 70s, a Win model 670, a 26" BULLBERRY custom for my Encore, the old H&R Jet rechamber and my pride, an old Rem model 30S EXPRESS full custom with a 28" Pacnor barrel that will keep 5 under a dime if I do my part.
Go for it!
You will love the round!
LONGTOM