Handheld Weapons Folder Location
First, we need to locate the folder which holds the Handheld Weapons.

1. Navigate to C:/BF2_Directory/mods/bf2/.
2. Open Objects_Server.zip.
3. Open Weapons/Handheld/.

Deviation (Accuracy)
First, we will modify the Deviation of a Handheld Weapon. This is basically the Accuracy.

1. Open the rulmg_rpk74 folder.
2. Open rulmg_rpk74.tweak with Notepad.
3. CTRL + F and type "ObjectTemplate.deviation" (or just scroll down and you will see it).

You should see the following lines of code:

ObjectTemplate.deviation.setFireDev 0.8 0.4 0.02
ObjectTemplate.deviation.minDev 0.8
ObjectTemplate.deviation.setTurnDev 0 0 0 0
ObjectTemplate.deviation.setSpeedDev 4 0.6 0.6 0.1
ObjectTemplate.deviation.setMiscDev 3 3 0.1
ObjectTemplate.deviation.devModStand 2
ObjectTemplate.deviation.devModCrouch 1.5
ObjectTemplate.deviation.devModLie 0.8
ObjectTemplate.deviation.devModZoom 0.8

4. Change the numbers around a bit, or just change it to this:

ObjectTemplate.deviation.setFireDev 0.03 0.05 0.01
ObjectTemplate.deviation.minDev 0
ObjectTemplate.deviation.setTurnDev 0 0 0 0
ObjectTemplate.deviation.setSpeedDev 1 0.05 0.03 0.02
ObjectTemplate.deviation.setMiscDev 1 2 0.05
ObjectTemplate.deviation.devModStand 0.9
ObjectTemplate.deviation.devModCrouch 0.8
ObjectTemplate.deviation.devModLie 0.4
ObjectTemplate.deviation.devModZoom 0.5

This will make the weapon quite accurate for what it is (It is the MEC Support Class Default Weapon - RPK74).

Damage
Next, we will modify the Damage.

5. CTRL + F and type "ObjectTemplate.damage".
6. Change the number (35) after damage to a number of your choice (do NOT exceed 95).
7. CTRL + S or File>Save.
8. Close rulmg_rpk74.tweak.