It is possible. You will need to obtain an Export licence from the Home Office. You will Also need to ensure the buyer holds the relevant licence for that country. An Import licence will need to be arranged in the Country to which you are sending the gun for this the buyer will need to provide the relevant paperwork.
If you are a buyer from outside the UK it is possible to export guns to most countries. You will first need to ask the seller of the gun if they would be happy to export it on your behalf. Some may be happy to do so, but if not there are several UK based shipping agents that can assist with exports please see below:
There are several UK based agencies that can assist with exports or imports. Please follow the links below: