How good is YOUR cover?
Here's a really interesting site. The proprietor, known as "Old_Painless", has done a bunch of testing on the penetrating power of various rifle and pistol rounds, complete with pictures. He tests padlocks, sheet rock, pine boards, bricks, and a bunch of other stuff.
Be sure to look under the "Miscellaneous" tests for the 45-70 results. WOW!
A big thanks to AnalogKid at Random Nuclear Strikes for finding this site.