Each weapon has its own parameters. There are 5 basic attributes that can be seen in the weapon's description after you tap on it.
1) Base Damage – The damage that one bullet can do to the enemy
2) Fire Rate – Number of bullets that weapon shots per minute (to calculate DPS, divide this number by 60 and multiply by damage)
3) Accuracy – The higher accuracy the better
4) Range of Weapon – Effective Range
5) Number of bullets in the clip