No problemo, Tom. I wasn't trying to change your mind, just rattling off why it works for me.
No bears in Texas that I know of, though, just lots and lots of feral hogs and an occasional alligator in some parts.
Re: 5.56mm, it's at its best in a barrel length of 16-20 inches. I like 5.56mm pistols, but with barrel lengths of at least 10 inches, preferably longer. With a 10-inch barrel, you probably won't see enough velocity to be really effective past about 100 yards, depending on bullet weight, ballistic coefficient, and muzzle velocity.
Les: Total agreement on barrel length! And yes, a flash can or linear comp is a good thing and money well spent! I think Gabe Suarez wrote in his blog (now gone) that he was very happy with an 11-inch AR with a buffer tube that was padded for cheeking but had no brace. I've seen a crutch tip used, but I think that's mainly so it will stand up in a gun cabinet without sliding and falling.
Wanting a really short (7.5 inches) barrel was why I went with 300 BLK. It doesn't suffer as much from a short barrel as 5.56mm, though the whole "it burns all the powder in the first 9 inches" thing is a myth. A 16-inch 300 BLK barrel will be more effective than a pistol barrel.
All these short barrels are REALLY LOUD!!!, by the way. Not always a bad thing in a defensive situation, but something to be aware of.
I also just really like the 300 BLK (7.62x35mm). It's a fairly efficient cartridge that can launch an impressive range of bullet weights, from down around 90 grain pistol bullets, up to the very heavy 250 grain subsonic loads. I believe its sweet spot in supersonics is around 120 grains. People compare it to the (more powerful) 7.62x39mm, but to me it seems closer to the 7.92x33mm Kurz, the cartridge used in the Sturmgewehr 44.
BTW, 5.56 is awesome fun in a Contender. When I was growing up, our neighbor had that very pistol, and I loved shooting it. In terms of range, though, I'd consider it a 100 yard proposition in most cases.
All my best,
Bob