The late author & firearms expert Robert Boatman; www.Boatmanbooks.com
has a few interesting www.YouTube.com
clips of him blasting away with his Glock 36 .45acp at some big ripe watermellons,
Boatman is an interesting character. I do not agree with 100% of his thoughts or remarks but he does have a easy-going style & tell-it-like-it-is manner.
His non fiction books are very detailed but not for those who get upset or irrate with ease re; firearms, politics, etc.
As for other ammunition test media, try wet phone books or newsprint or Knox & Kind brand gelitin(check correct spelling, Im saying Jello).
Old gallon milk jugs filled with water(or a few frozen) could help too.
Be safe and make sure you are aware of your backstop,