"weapon_normalmap_fix" and  is for those using the normalmap plugin. If you use weapon_highfirerate.dat while using normalmap, then you will likely experience a bug where your character stays illuminated by the color of the muzzle flash. This is caused by the new very high fire rate for the MAC-10 and TEC-9, so weapon_normalmap_fix slightly decreases the fire rate (still an increase from the original though). 

Also, don't forget to rename either of these to just weapon.dat whichever one you use.

Some of the changes:
-AK now has slightly higher damage per shot than the M4(M16), but is still less accurate and has a slightly lower firing rate.
-Higher fire rate for the Desert Eagle, Micro SMG(MAC-10), TEC-9, SMG(MP5), and M4(M16).
-All weapons have slightly increased range.
-All weapons have realistic ammo capacity (MAC-10, TEC-9, and MP5 have 32, AK/M16 have 30, country rifle (I use the M1 Garand) has 8, and the sniper rifle (I use the Dragunov) has 10.
-Minigun's range has been doubled, but inflicts slightly less damage per shot (rate of fire is still the same though).