Nice little read.
http://www.rifleshootermag.com/ammunition/centerfire_22_biggame/

Not exactly about Bell, is it? However it does raise a good point, it doesn't take much to kill if you get a bullet into the brain or heart. However you must get it there. I believe there is a criteria you can use to guesstimate penetration, sectional density. Next to bullet construction this number tells you more about the penetrating qualities of a bullet than does velocity. I like a bullet with a sectional density of .250 for catch as catch can hunting where you might shoot a deer, black bear, boar or even a sheep. Bullets with that kind of density include 125 grain 6.5mms and165 grain .30s. the .270s 130 grain and 7mms 140 grain bullets are only a tiny bit less. All known for their deadlyness on medium game up to roughly 400 lbs. How many .22 bullets can claim such a figure?

Looks like the 75 grain .224's run a SD of .214; about as good as it gets, but it calls for twist that reportedly tears the usual varmint bullets up just due to spin. I was grateful when the Army decided the old 5.56 ball was just too light and went to a heavier bullet and lower twist. But I am retired now (hope it stays that way!) so I will have to let the Mattel Toy live out its silly life.

Interesting that Boddington excluded the .22 Hornet, which has (roughly) the same foot lbs as a .357 Mag at 100 yards. Heh, heh, I read an old article from back in the days the .357 was introduced, some gun writer guru took it out for Grizzly. We would commit him in these parts. Hope I haven't offended those hunting the big bear with 357's. We all have our thing.