Originally Posted by oldpapps
They will be harder, thicker jacket and maybe lead. I wouldn't expect a great deal of expansion at pistol velocities.
Recommended muzzle velocity range for the Inter-Lock line of bullets is 2000 to 3300 fps. So no, you won't be getting good expansion. Inter-Locks are obviously structured for rifle velocities. The .429 .300 grain XTP on the other hand, has an expansion range from 700-1500 fps. http://www.hornady.com/bullets
.430 is fine for loading in the .429 though, so you have no worries there.