I have fired many different types of ammo of .45 ACP's and .40 S&W into all types of backstops/targets. Whether it was pumpkins, wood, metals, old rolls of carpeting, sand, etc. The .45's never impressed me with their lack of mushrooming on the softer items. The .40 S&W's mushroomed much better for me. Must be the difference in velocity.

Just my .02