I am going to America later on this year, and I was considering getting a crossbow while I was there. I wanted to know if it was legal to bring one back. I'm 19 years old, so I am past the age limit and I know that you don't need a licence. But I was wondering if I can bring it back in the hold luggage (with the strings taken off of course).
The British Airways luggage restrictions (in the Firearms and ammunition section of Prohibited items; sorry, but it's not possible to give a direct link) say that you can bring a crossbow in your checked luggage, without needing to notify the airline in advance. (Unlike, e.g., guns, which require 72 hours' notice.) However, you would need to check the regulations of the particular airline you'd be flying with.
I've not been able to find anything about import restrictions of crossbows into the UK. The government's guidance Guns, knives, swords and other offensive weapons: UK border control doesn't mention any kind of bows but, as far as I can see, bows aren't counted as offensive weapons in this sense, since they have legitimate sporting use. A brief Google didn't turn up much: archery forums seem to be of the opinion that you're free to import such things but, of course, you may need to pay import duty or import VAT depending on the value of the bow.