Interesting observation. took a spinner made of 3/16 steel and hit with my .22 Hornet 45 gr HP's at a distance of 110 yds and also rung it with my .243 using 100 gr federal sierra game kings.
Well the hornet left a bigger hole in the steel than did the .243. whats up wit dat ?

I don't know much about the ballistics of either round, but my assumption would be that the 22 hornet is moving a bit slower allowing the bullet to deform more on impact while the 243 is just blowing through.

Idunno is right. The Hornet si going quite a bit slower then the 243.

actually it not that much. The Hornet is right at 2700 fps and the .243 is 2960 fps. Whats also amazing is the little 45 gr hollow point blowing through the 3/16 steel. I thought it would just dent it and spin the little gong.