This is an interesting question. There are three types of ballistics: 1) internal ballistics (or what happens inside the firearm), 2) external ballistics (or the flight of the bullet), and 3) terminal ballistics (or what happens when the bullet strikes the target). The question involves the external and terminal ballistics. In general, the energy a bullet has when it strikes the target is a function of mass and velocity. Modern rifle cartridges like the 7.62 NATO have relatively high velocity (e.g., 2800 fps) and low mass (147 grains). Civil War rifle muskets have relatively low velocity (1000 to 1500 fps) but have high mass (500 grains). Despite its low velocity, the Minié ball packs a powerful punch. 300 yards is well within the lethal range of a Civil War rifle musket. Some ballistic gel tests have indicated they could penetrate 3 soldiers, especially in soft tissue (no large bones). If the Wade doors in question are soft pine or poplar, then the bullet could have easily passed through the doors and still have enough lethal energy remaining. If the doors are thick hardwood, then I doubt it. I have a US Model 1866 2nd Allin conversion that I shoot. It is a US M1863 Rifle Musket that was converted to a single shot breech loading 50/70 cartridge gun. The 50/70 is a 50 caliber round with 70 grains of black powder. This is similar in ballistics to a 58 Minie ball. It was a favorite of buffalo hunters. I have not tried shooting through boards, but I may try this sometime.