While hunting down sources on why the military ended up with the .223 round I came across an interesting reference. BTW, Let's not start a flame-war over the British in Africa Blah, Blah, Blah. Apparently the British hired an Kenyan white-hunter (they probably hired a bunch, this was not uncommon as they tended to shoot well under pressure and know the country)to track down and kill members of the Mau Mau insurrection. Since he was a hunter, he used his own rifles. With as many of hundreds of shoots to his credit he felt the most effective round was the 22-250. Dropped a man quicker than anything. Apparently, at least according to the article I was reading, this was an important bit of anecdotal evidence in the move to a smaller, faster round for the US military.

Unfortunately, the details and sources have become kind of scrambled over time and I would like to refresh them. I'm guessing someone on this board might know. Any ideas?

I thought the 22-250 was out around 1965 or so.  Wasn't the 223 in development in the 50's?  I think you should double check your sources.  There were wildcats out before the 22-250 which might be what you are talking about, but the 223 (1964) was out before the 22-250 (1965).

Could it have been a reference to the .250-3000 or .250 Savage (the parent of the .22-250)?

Like I said, the details are sketchy. I'm just fishing. When was the 220 swift out?

The .22-250 was out as a wildcat almost as soon as the .250-3000 hit the scene (1915). Browning offered factory rifles for it a couple of years BEFORE Remington standardized it. Moving on, Les Womack was trying to make a case for the effectiveness of high-velocity .22 centerfires during the '40s when he was tasked with eradicating wild burros in Arizona (see Killing Power in Volume I of P.O. Ackley's Handbook For Shooters & Reloaders). So yes, I think your information is very likely true.

When was the 220 swift out?

1935

It might have been the swift. I remember is was a high-velocity .22 round, not a 6mm or anything. I also remember thinking it was an odd caliber for an African white-hunter type. They seem to usually have an assortment of military caliber rifles and the big-bore stuff.

There were some other factory high-velocity .22 centerfires out early as well: the .22 Savage Hi-Power (introduced in 1912 and always popular overseas) and the .219 Zipper.

The Swift was out in 1935 and it was a very popular caliber, so I think that IDK is right.  Definately was not the 22-250, even though it was around in very rare wildcat rifles.  The English aren't like Americans with wildcat cartridges.