What country are you in?
Many countries, including the UK, have strict laws regarding possession or making firearms or parts and even items that look like them.
You need to get propeer legal advice but my layman’s view of current UK law is:
You can own a vintage functional “cap & ball” or pinfire revolver but not use it or carry in public.
You cannot own or make a “realistic”model of a revolver, or other firearm, even made of plasic unless you can prove you are a re-enactor, film maker or similar. There is an exemption if significant parts are brighly coloured to indicate it’s not real
To own a “deactivated” modern firearm it must be deactivated to the lastest standard on transfer and has to be registered.
You can own a fully operational CO2 powered semi-automatic air pistol that is identical in appearance to a Glock, browning etc if over 18 with no licence required.
No it’s not logical, but some of he offences carry a mandatory prison sentence.
Robert.