Back in the day ballistic gel wasn't a thing. In every article I have read from the 19th century or early to mid 20th century, factories and people alike have used pine boards to test the penetration of bullets.
Someone would stand at close range, somewhere between 10-15 feet and shoot the boards. And from the results they would have a rough estimate of the caliber's penetration capabilities.
Well... I tried it today. I took my 1886 chambered in 40-82 and aligned some half-logs that I had cut to make notches in a small log cabin im making. I thought that it would maybe go through 5-8 pieces of wood MAX.
I was wrong. I had 10 stacked up. Went through all of them and blasted out the back into the dirt. Never to be found.
These old cartridges have a decent amount of punch!