They may be had anywhere from $25 to $125.
You need a gunsmith.
gun shop, gun show
About $150
Your best bet is to take it to a gun shop or gunsmith and have them actually show you how.
i dunno how old this question is but i learned that the cobra CA380 that i had just bought is in fact the old Davis p380. the parts from cobra and Davis r exactly the same , cobra just bought the rights to it. if u look up the cobra website u can find parts for it
50-100
Just sold a derringer 25 Davis for $75
25-80
50 USD
25-100 or so
25-65 USD or so