Beng: the empty hole/slot on the bottom of the magazine area is for the en-bloc clips to fall through after the last round has been stripped from it/them and chambered.
I owned two back in the day, and worked for a Warren Commission sub-contractor while testing the imported Carcanos for accuracy to prove that Oswald or Oswalds rifle was capable of hitting and killing Kennedy at the distance he was shot, which was about 60m. It was a easy shot even with open sights. We tested about every configuration of Mannlicher Carcano we could lay our hands on from distribution houses: The long barrelled 1891s (??) were very accurate if they had not been shot out.
The Carcano uses/used a 'gain twist' rifling system, like cannons and artillery pieces, and that is/was very accurate system. The Italians developed the M38 which was a shortened version of the 91. Some were made in Turin at one plant and some in the Beretta plant, I believe. Some M38s were made, and I believe those made early on during/for the war years (1937-44)were made properly with either new barrels or properly shortened barrels, which I think is shortened from the breech end, not the muzzle end but toward the end of the war as manufacturing began to suffer, some barrels were simply shortened without regard to accuracy. As Rex said, if you cut the barrel back, from the muzzle, you wind up with a piece of junk as it is the gain twist in the last 6" or so of the barrel that gives the heavier bullet its accuracy. When shortened from the breech or chamber area and rechambered, the gain twist was retained and the bore kept closer to the .264 of other (Japanese, Swede, Norwegian) 6.5mm bores.
Those M38s with properly shortened barrels were both accuate and handy. The 6.5x52mm Mannlicher Carcano round is nobody's wuzzy and is effective way beyond 200 yds. I used one extensively to cull herds in Colorado in the mid-60s. I also found that my accuracy using the Hornady .264 daimeter bullet was excellent and I quickly became sold on the capability of the 6.5mm bore, especially with heavy (160) gn slugs. I found I needed to go to a heavier caliber only if I was likely to encounter bear.
I like my 6.5s. I like my 6.5 Swede and use it quite a bit but that is only because I have not yet obtained a 260 Rem. When the 260 came out I thought it appropriate that we finally upgraded the 6.5mm bore. I think a 260 or a 6.5 Creedmoor would make the perfect mountain rifle or scout rifle. jmtcw.
