I actually just shot my Carcano M1891 (mfg in 1897) today! I love the thing. Although most Mannlicher based actions have a long reach to work the action (reaching up to the bolt handle), they are very sturdy. I am getting a M1891 cavalry carbine later this week.
In my own ballistics tests (involving bricks, sandbags, and quite a few other things) the 6.5x52mm round is just as effective as something like 8x57mmJS (used in things like the Gew. 98 rifles and many others), the 7.62x54R (Mosin-Nagant) and .303 British. The only downside to the Carcano series rifles was the Mannlicher en bloc magazine. While being faster to reload, it couldn't be single loaded and was an entry point for dust and dirt. Even my refurbished M1891 had some sand left over in the magazine from Africa (in the grease of course).