When the Trojan was introduced, it was only offered in very limited barrel lengths -- 12-gauge 28- & 30-inch and 16- & 20-gauge only 28-inch. The 1913 Trojan flyer --
1913 Trojan Grade flyer.jpeg
1916 catalog --
1916 Trojan.jpeg
By the 1923 Parker Bros. catalog the 26-inch barrels had been added to the offerings --
1923 Trojan 26-inch barrels added.jpeg