.223
Your post has about 3-4 angles to it. I'll try and hit the high spots.
The .223 is underpowered in the sense that there are certainly cartridges with higher performance. In the hunting rifle world, performance wise, the .223 is a varmint cartridge. The cartridge will kill deer, it will even kill deer efficiently in many instances, but it needs to be properly loaded with the correct slug, and shots need to be placed well. There is now a whole line of .223 slugs intended for deer, and using same, it can be used as a "deer" cartridge. Not ideal, but it can suffice. My boy took his first few whitetails w/ a .223 bolt rifle and 62 gr bonded soft points from I think Federal. The last one he shot w/ it, ahead of the diaphram, but farther back than I would prefer, left exactly a zero blood trail for 40-50 yds. It go into thick cover in that short distance and could have been lost I suppose, had it gone much further. The bullet did not exit, the hide covered the miniature entrance wound, and we had an interesting lesson in deer tracking and ctg performance. He shot his next deer with a 7.62x39 bolt rifle. with the results you'd expect. The x39 can be had with slugs as heavy as 150 grs (I shoot 135-130 gr) and penetration and exitwounds occur consistently on deer. The comparison to 30-30 is apt.
The Mini family are great rifles. Wood stocked (well some are) blue steel (same same) and a time tested action. My Mini is in x39mm, but I have shot plenty of Mini-14's in .223 of course. The 6.8 new comer leaves me cold. Great cartridge performance wise, but not common. I wouldn't have one.
The .223 drew bad press as a military round early on. Again, it is just not a .30 '06 or .308. The combination of of hight twist rates, and heavier and heavier slugs to stabilize same, and shorter carbine barrels, reduce its velocity and increase stability, reducing the slugs tendency to yaw and tumble, which it needs to do, to wound effectively in the FMJ and AP varieties issued to the military. And in the mtn and desert terrain, I read the .223 is not reaching like it needs to in some fights. The military's search for a new cartrige is further indication of its shortcomings in the current war.
If I had to have a Mini, and I intended to hunt deer and hogs with it, I would go with the MIni-30. If I wanted a GP rifle that I MIGHT hunt deer/hogs with on occasion, but would spend more rounds blasting away at paper and steel, and have it do double duty in the HD/SD role, I'd get a Mini-14 and load it with appropriate slugs as the task at hand required.
