Some time ago, i purchased some of the RWS Superfield Fieldline pellets [Batch number ending in 528.]
These were superb and comparable to Air Arms or Exact, but quite a bit cheaper.
I recently purchased some more [batch number ending in 642] , but chose to return them, as they appeared to be of a different composition of metal and differed
in size also. Downrange, they did not group as well and the average zero was around 2 inches lower.
Through the chronograph they were around 30 f.p.s. slower as well. Beware of purchasing any from this batch if you are relying on them for F.T.!!