Sam has two muzzle loading pistols. Yet when he fires them, a fixed ammunition bullet, still in its shell casing speeds towards Bugs. So, there are two mistakes here: 1) the muzzle loading pistol firing modern fixed ammunition bullets and 2) when the pistol is fired, the bullet flies towards Bugs still in its casing.
When Yosemite Sam and Bugs Bunny are at the base of Hoover Dam there is a slot machine there. Bugs wants to put a quarter in the slot machine so he can gamble but Yosemite Sam says he was putting his last quarter in the machine. Yosemite Sam then proceeds to pull the handle on the slot machine without ever actually putting his quarter in.