Hello... I really like the Bisley Model myself. Below should answer your question my friend. Have a good one.
Bisleys were serial-numbered in the range of 156300—331916, in the same sequence as the Single Action Army. All Bisleys after No.161,376 had "BISLEY MODEL" with the caliber stamped on the left side of the barrel, which is rare for older Colt revolvers. The most common calibers were .32-20, .38-40, .45 Colt, .44-40, .41 Colt, and the British calibers .450 Eley and .455 Eley. A total number of 44,350 were manufactured. Production of the Bisley was terminated in 1912, but serial No. 331916 was shipped after the First World War. Most Bisley Standard Model Revolvers shipped to a United States address were not used for target shooting, but for self-defense, because the grip and hammer were ideal for fast shooting.