Robert Arnold's Book The Conspiracy Between John Wilkes Booth and the Union Army

[Gene C]

I don't know much about Civil War weapons.
Is a Spencer Carbine a high velocity riffle?
I would have thought a high velocity bullet at short range would have shattered the neck bones.
From the short distance between the shooter and Booth, not more than 50 feet, could a decent pistol cause the damage to the neck bones?
Is this the same Jack Garrett that claims the man in the barn was Booth?

Sorry, but this is a busy time of the year for me at work, and my time to research these things on my own is limited.