But here in NH including the place i will be hunting at doesn't really offer "clear" shots past say 50-100 yards. I feel like a .223 with good shot placement can easily handle that, isn't that so?
While I still feel that it's a marginal cartridge for deer, but given your range parameter (short) ..... it could be done well with the right gun and load ......
The .223, with it's relatively tiny bullet, relies heavily on very high velocity for it's "killing power" ..... the problem that often comes up with the small, soft pointed bullets at these velocities is they fragment on impact, leaving large, but shallow wounds...... fatal, but not in the immediate sense required for swift recovery of your deer ..... Deer are not paper targets, nor armored vehichles, but living, breathing animals ....... poke a decent sized hole in their heart and/or lungs, and they WILL die...... and in short enough order, that it should be relatively easy to find them ..... punch a decent sized hole deep enough that the bullet exits out the far side of the chest and there will be ample blood on the ground to point the way to your prize that even Stevie Wonder could follow ......
To that end ........ IF one were going to use a .223 on a deer, the bullet should be one that is designed not come apart at expected impact velocities, is as heavy as possible, and should be driven as fast as possible ..... and To THAT end, the gun should have a rifle length barrel (20+") with a fast twist ( to stabilize the heavier bullets) ......
Hornady offers a 70gr GMX bullet that they claim to drive to 3050 f/sec with 37.1gr of CFE-223 ..... From a 20", 1:7 twist DPMS Ar-15 ..... that's 980 ft. lbs of energy @200 yards ..... on par with a 150gr 30/30 load .... without the holdover ...... if I could find a box of these (can not) and be assured the GMX would still open reliably at 2400 f/sec ...... this might make for a good second "little kids' gun" (Currently have a 7-08 Ruger Frontier that I download just a bit ...... but have two kids that both want to use it this season .....)
..... at the ranges you are contemplating, that load, as advertised, would have more than enough energy, bullet expansion and penetration to kill a deer if you put the bullet through the boiler room, from just about any angle (not recomending a Texas Heart Shot, whatever the caliber) ......