Learning more and more about reloading and developing some really decent loads for my .223 Rem. and .308 Win.

I recently bought a partial box of .224 Speer 55 Gr. Hollow Point "TNT's for my .223. Speer states on the bottom front of the box "Designed for 22-250 Rem. and 220 Swift Cartridges". Why they say this? I know they will work in my .223; but why optimized for 22-250 and 220 Swift. Do they expand in these calibers better? I imagine any optimization is internal but being relatively new, I just don't know. Thanks for any insight....

Brian