Corrected entry: During the gas station shooting scene, the shooter puts several bullets in the trunk of the yellow car. Steve Martin takes this car to get away from the shooter. When he pulls into the lot where the carnival employees are, there are no bullet holes in the trunk of the car.
Corrected entry: When Steve Martin is being shot at by the sniper, he ducks into the garage behind the yellow car. Just as he does it, a hail of 7-8 bullets hit the trunk of the car like a machine gun sweep. However, the sniper is using a bolt-action single shot rifle and cannot fire at anywhere near that speed.
Correction: The sniper is using a m16/ar15 type rifle. Most likely a semi-auto Colt model 655 or 656 with a 20" heavy barrel, fixed stock, scope and sound suppressor. The rifle is shown with a magazine capacity of up to 20 rounds. in addition the sniper sports dual Mac 10 assault pistols and a revolver.
Corrected entry: When the robbers are driving away with the church Navin says "It's a blue Chevy two-door going south on Hertado Street." They are going down the street the gas station is on, which is also where Navin lives. Later on when the sniper is picking out a target and he lands on Navin's name in the phonebook, it says he lives on Elm Street.
Correction: The gas station could have been located on the corner of Hertado and Elm, with a numeric address on Elm Street.
Correction: Just watched that scene. The bullets are very visible down the side and the back.