This is not a real firearm. It is a wooden & rubber television stunt prop and it cannot be made to fire any type of projectile whatsoever. These prop rifles were used on both WHO & Torchwood (See the screencaps).
This one is pretty beat up so it is priced accordingly. It is large and heavy! The item "Doctor Who original screen used stunt prop Dalek Tommy Gun Dr. Who Torchwood TV" is in sale since Tuesday, October 20, 2020. This item is in the category "Entertainment Memorabilia\Television Memorabilia\Props\Originals".The seller is "gaijinryudojo" and is located in Sykesville, Maryland. This item can be shipped worldwide.