Nowadays is maybe not the right time to go and visit Darra Adam Khel, especially with the terrorist threat. Darra Adam Khel is a gun workshop village 30km south of Peshawar in a tribal zone administrated by the Affridi tribe (Pashtos).
To go there from Peshawar, there are two options: you can go by bus (ask the bus to Kohat and get out at the entrance of the village), but you will risk being sent back by kashadards, the local tribal police. Permits are not delivered anymore by the Ministry of Tribal Affairs in Peshawar because of security reasons, and theoretically, you are not allowed to go there. However, there is another option: going there illegally with a guide and a driver (ask for them at your hotel if you are not approached by a guide).
You should go through the checkpoints without problems if you say you are going to Kohat. At first sight, Darra Adam Khel looks like any other village in Pakistan, but if you look closer, you will see gun shops and behind the main street gun workshops. Your guide will give a bribe to khasadars and you will be able to visit the village escorted by two guards.
At first, I was offered delicious tea from a huge samovar and I was shown three different types of guns (Kalashnikovs and pistols) that I could manipulate. It is said that a gun maker in Darra can duplicate a gun that he has never seen previously in ten days (three days for the further copies). 400 to 700 guns are made in Darra every day and sold to smugglers or Afghan warriors.
I was authorized to take as many pictures as I wanted; the gun makers were quite friendly and were proud of their skills. Also I could hear some gunshots near me: guns being tried before being sold.
I was also proposed to try some of the guns for an extra price (not cheap, though; prices are barely negotiable). If you decide to try the guns, you will be taken into a backyard in the village where you will be able to shot on a rocky hill; you will also be given some explanations on how to hold a gun.
Only for the very adventurous, this excursion is not really recommended right now because of the problems in the tribal areas (in 2005, it was safer).