A little background, my father in law debated me one time, 243 is the best deer cartridge. I said, naw, it's the 30-06. He said no way, the 243 kills them just as dead, sweetest shooting cartridge with no recoil, and very flat and fast.
Shortly after that, I 'd gotten on a lease and bought a 243 as a back up to my trusty 30-06 and for my father in law to use when I took him as my guest. Well guess what? I've come to believe he's right. I've shot deer with calibers up to 375H&H and pistol calibers 45 ACP and 41 magnum and nothing kills deer as quickly as that 243.
Since then I bought a small frame 243 Tikka T3 for my kids to use as their first deer rifle. That gun is a tack driver and kills deer dead right there. It's light, smooth action, relatively inexpensive, sized right for kids and comes with shims to grow with them. My buddy took his youngest of three sons out to hunt his first deer this weekend. Borrowed that 243. One shot, DRT! Loved the gun.
Just more proof in my mind that my father in law was right. The 243 is the best deer cartridge. I don't know what it is, speed? sweet-spot diameter of bullet? Just the right amount of energy? Love to hear others' thoughts and reactions, both pro and con!