RWS miesterklugen (?) from Ramsbottom £6 tin and they come in various sizes so you can work out which your gun prefers, better pellets tend to be softer so fit to rifling easier and anything that gives a specific size will probably have a tighter spec. If you really want to get into it you can size the pellets. With my lp 50 and b96 I use pellets that are a tight fit into the magazine as this tends to size them as well as holding them to prevent stoppages.