Call of Duty Classic

Can be done during the first mission after training.

I didn't find any extra pistol ammunition but if you are conservative with your ammo you should be able to get through the mission with bullets to spare.

Obviously, playing on the lower difficulty levels would make this one easier.

One final note, resist the urge to whack the first German in the back of the head :-P I forgot the 'no melee attacks' condition first time round!

This was done on 'Greenhorn' difficulty, so it may be different for harder settings. During the American missions, there is a section where you must defend a town and take out a couple of tanks with a rocket launcher. After you do this, you'll enter a car. From this point onward, use nothing but the pistol until the achievement unlocks. Should you use a melee attack or fire another gun, simply restart the level. The game will put you in the vehicle at the start of the car ride section.

While you're in the vehicle, you don't need to shoot anyone. Enemy soldiers will follow you. You can shoot them, and they can shoot you, but it's best to leave them alone and conserve your pistol ammo. Minimize their threat by not leaning out the window. I got shot an average of three times, whether I fired back or not.

The nice thing about this solution is that you will only have to kill 8-10 enemies, at relatively close-range, and they appear no more than three at a time. Once on foot, there are: 3 enemies in the first building you enter, 1 outside around a corner to the left at the dead end, 3 across from him on the right, 1-2 in the next street, and 1 upstairs in the buiding with the new car.

Defending the car/getting in the car seems to be the hardest part since the bad guys are out of effective range with the pistol. Just take cover inside and wait until your CO tells you to get in, then do so quickly. Once you're in the car, you're home free.

First real mission after training. Let the planes blow up the house. Then stay behind the AI for the rest of the level. You can use the pistol you start with and not need anymore ammo. Pretty straight forward.

Here's video that I found a while ago... AH puts out some good videos with explanations. Here's the description from Youtube:

Call of Duty Classic: Pea Shooter Achievement Guide

Geoff shows you how to get the Pea Shooter Achievement in the XBL Arcade game, Call of Duty: Classic.

You might as well pair this pea shooter achievement/trophy with the survival achievement/trophy.

For the Pea Shooter achievement/trophy, you must clear the mission using only the pistol and no melee attacks. If you happen to use other guns and/or melee attacks, you'll void the achievement/trophy.

For the Survival achievement/trophy, avoid dying and reloading last checkpoint. If you die, you'll lose the achievement/trophy.

If any achievement/trophy gets voided, you'll have to start over.

May be possible on any difficulty, but I would recommend doing this on the lowest difficulty. Achievements/trophies pops if you clear the mission using only the pistol without melee attacks and dying.