Whether you use them for cosplay or for theatrical productions, prop pistols are more than just costume accessories. Depending on the degree of fidelity, some may even require licenses especially in states such as Victoria. Although prop pistols are only replica guns and not real weapons, there can be concerns when you intend to carry the props in public.
As a general rule, anything that one markets specifically for children and clearly cannot be mistaken for a true firearm is usually safe. Queensland and Western Australia generally allow the sale of non-functioning replicas without a license, but this is not true of the rest of the country. Always check with the local authorities before considering an accurate pistol prop. The penalties for failing to comply with local ordinances can be very stiff.
Types of Props
Note that these rules apply to anything that looks like a weapon, including many science fiction replicas. This is one reason why many pistol props resemble flintlocks and other historical devices; it's much easier to make it clear that they are not in fact real firearms, but instead fall under the category of miscellaneous costume accessories.
Prop Pistol Materials
With the restrictions against accurate replicas, a large number of prop pistols are plastic. Not only is it light and easy to work with, but it minimises the chance it will be mistaken for the real thing. Metal is often a material in various toys like cap guns, which carry a bright orange tip so as not to be confused with real weapons.
Owning Replica Pistols
One of the most important things to remember about replica pistols is that the more they resemble a real weapon the more you have to treat them as one. Many jurisdictions require safe storage as well as ownership permits, and public display is usually prohibited. Take the time to learn your responsibilities with any replica.