Victor, this rifle does hold 13 rounds in the tube. I know an owner. I think the discrepancy comes from the tube 13rd capacity being mistakenly listed as 12 + 1 (13rds total) by some retailers.

while I would normally say that Cimarron is correct in this case I am not sure as all the other retailers also list it as 12 and cimarron lists all the 1873 sporting models with the same 13+1 capacity I recommend calling Cimarron and asking them to be 1005 sure (1-877-749-4861)