This question arises from an 1845 newspaper article about the "Ballinhassig Slaughter" which was a confrontation between civilians and police that ended with the police shooting dead between 8 and 11 people. The following was said during the coroner's inquest:
Now, I know that with modern firearms, the exit wound is generally bigger than the entry wounds Further, it would appear this holds true for Civil War muskets; however, that same article makes it clear that the newer Minié ball created much more devastating wounds. I can't find anything specifically about pre-Civil War muskets c. 1845.
If an exact weapon is needed, my first guess is that it was the Baker Rifle with my second guess being the Brunswick Rifle. Now, I imagine the same thing holds true and these surgeons are correct in their assessment that entry wounds are smaller than exit wounds; however, I wanted to be sure, because if this rule of thumb, for some reason, changes for lower-velocity balls, it would render the surgeons' conclusions reverse. I appreciate any help you can provide.