1.Copy the text from the weapon folder into weapon.dat

for example if you are using the m21 then copy the contents of the text into the weapon dat provided in the folder "Re 7 weapon dat"

Notes from me : I can't modify the knife's damage in the weapon dat because there is no damage entry in the file
(If there is an entry for that,i can make the survival knife damage mod - it's more damaging than pocket knife in the RE 7)

The changes :
The smg (p19) has 64 rounds
The flamethrower (burner) has 150 rounds
Etc.