bill-in-texas
US Veteran
The standard length barrel on the 1897 was 30", at least for 12 gauge. I don't recall on 16 gauge.
You're more likely to see longer than 30" than shorter. It seems that 30" and 32" were more popular than 28" and less in '97s. Of course that's other than the trench/riot guns.
UPDATE: I just ran a cleaning rod to the breech face. The barrel is in fact 32".

-Bill