It is somewhere in the 1500 to 1600 range. I had one with 15?? that was not hooded and the one I shoot is around 1620 and is hooded.
Edited on 5/23/2020. After Jim R posted that he sold a 14xx with a hooded barrel, I went back and looked at my records and I think I got mixed up. I used to own 1221 and 1546 along with several older and newer guns. I know 1221 was a non-hooded barrel and now believe that 1546 was a hooded barrel so the range is probably somewhere in the late 1200 or 1300 range when they switched. It is always possible that they made both versions for some short period of time.