So there you have it. At least one Zouave with rifling following Ordnance Dept. specs and another with a totally different type. I believe Remington made top quality arms for the government, however the Zouave was an oddball. Some say it was the best designed rifle of the War, and it was a good weapon, but it was also a conglomeration. Stock, buttplate, triggerguard and sights of M1855 pattern, barrel bands like those on the M1863 Type II (M1864) and barrel and lock from the M1841. The patchbox found on these is like the one found on the M1855 rifle-muskets after 1859.
I was thinking that perhaps the Zouave described above with seven grooves may have been barreled with a M1841 barrel. In 1845, Remington took over a contract for 5,000 M1841 rifles defaulted by John Griffiths. They received another contract for 7,500 rifles shortly afterward and in 1851 another contract for 5,000 more of the same model. Remington was tooled up for this barrel. If I read my "Small Arms 1856" book right, the regulation M1841 Rifle had seven groove rifling, since the testing officers stated that they wanted to reduce the number of grooves to either three or five and making them shallower. So, The above mentioned seven groove barrel, if .54 cal. would be a leftover from probably the 1851 contract. If it is .58 cal., I'd say it is a good possibility that Remington used the seven groove rifling guide for some of the barrels of the 1862 Zouave contract. As I write, I see in Gluckman's book that Zouaves have been found with barrels with the standard three wide grooves and barrels with seven narrow grooves at 1 turn in 5 feet. So either would be correct. We can only ask the questions, when did they change and why?