Q: And what conditions do I have to meet regarding its storage? I have two lovely old Damascus barrelled guns – including a bar-in-wood Purdey, that I would like to use game shooting, but I daren’t put them through the proof house for nitro proving, just in case.

David says: Provided the guns remain in black powder proof there is no reason why you should not use them. Your firearms licensing department issues explosive licences for what are known as shooters powders. You must demonstrate a good reason for having one. Possession of, and intent to use, a gun that is only proofed for black powder is a good reason. There are quite stringent requirements for the transport and storage of black powder and you can get guidance from the BASC website. You need an “acquire and keep” certificate. The cost is £24 and £15 on renewal.