For wet newsprint, make certain you soak it thoroughly for a minimum of 24 hours, and make certain you keep the media packed similarly for each shot.
Keep in mind, too, that densely-packed medium will be much tougher on a bullet and generally create more expansion than flesh and blood. A more representative sample can be gained by positioning the wet newsprint in one inch sections offset by an inch of water and an inch or airspace. Put into a repeating setup will give you results which are very close to what one may expect on game, though there is no true replacement for the real thing.
Years ago, I decided to create such a setup, and while the partitioned sections were a bit tricky to figure out (for me at least as I am not mechanically-inclined), the results offer a rather consistent look at projectile performance and can give one a clearer idea of what to expect on game.
Taken from game/impact vel. app. 2245 fps:
Taken from test medium (TTSX on left & TSX on right):