We do need to straighten out the canons frettes definition. It's one of those that requires more than a couple words. "Sleeved" doesn't really do it, as we understand "sleeved" in English--which is cutting off old barrels and fitting new ones into the chambers. "Canons frettes" can also refer to the original barrels, as in the design of perhaps the single most popular French shotgun of all time: the Manufrance Robust.