do any of you guys know....

Anything about this 5.57x28 cartridge? Is it available is a semi auto handgun? Or is it strictly a rifle ctg? 8)

YES.
NO.

There is definitely a FN Five-seveN (FN's actual spelling) pistol available in 5.57x28. I have a friend who has one and I have fired this pistol twice. It handles and shoots almost like a 22 LR pistol. There are probably other 5.57x28 pistols on the market, but this is one I'm familiar with seeing and using.

Masterpiece Arms produces a Mac10 style pistol chambered in 5.57x28. God awful expensive ammo though.

not familiar with a 5.57x28 although there are several googles seemingly using that term interchangeably with the FN cartridge 5.7x28..

as mentioned above, the 5.7x28 pistol is marketed as the FivesevenN emphasizing their initials in the caliber name spelled out..

as far as the applicability of the 5.7x28, the FN PS90/P90 [FA selectable] bullpup carbine and the FN FiveseveN USG/MKII polymer pistol are probably the most prevalent..

I have read about some AR applications although I have never actually seen one or fired one in person to rate its usefulness..

the 5.7x28 [.224"] cartridge was developed for specific military purposes and doesn't seem to have migrated much beyond the two basic FN platforms..

hope that sheds a little light on the subject, cheers : )

OK guys, thanks.... 8)

You might want to check out the 22 TCM. Similar performance, maybe cheaper ammo.

http://the-zombie-hunter.blogspot.com/2011/08/small-bullet-bit-hit-new-armscor-22-tcm.html