Reloading 6.5 carcano

[Bruce_in_Oz]

If Carcanos bores are anything like a lot of other rifling systems developed in that era, the bullets will be theoretically "undersized". The standard theory of the time was that the swift kick in the backside at ignition would "bump-up" the rear of the bullet for a reasonable seal and everything would be OK. I have never seen a recovered bullet that had been fired from a '91 Carcano, but if anyone has, could they take a close look at it. If it is not too mangled and distorted, see if the rear-most four or five millimeter is measurably larger in diameter than the rest of the bullet jacket and if there is a visible difference in the depth of the rifling marks on the jacket, from front to rear. i know that the original nickle alloy jackets are relatively hard, but they had to be softer than the barrel steel for the rifling to engrave the bullet.

Another interesting theory that is discussed in early technical texts is that leaving a bit of "soot' in the barrel after each shot was a good thing, as the heat of the next cartridge that was fired would cause any atmospheric oxygen in the barrel to react with the "soot" and not the barrel steel. As in any rifle, the idea was for the bullet to engage the lands to cause bullet spin, but NOT for the bullet to be so hard that it acted like a high-velocity broach and just tore out the lands. .303 Lee Enfields work exactly this way: .311" bullets, .303 Bore, but a nominal groove diameter out to .319" was within spec. as per the drawings I have. It seems to work way out past 900 yards, as all the older target-rifle types will tell you.

If the BORE diameter (across the LANDS is smaller than the Jacket diameter. (Bullet .264", bore .258 or so, "conventional bullets, and a "fast-ish" propellant may just get the job done nicely, bearing in mind that "sporting bullets generally have CLOSED bases as opposed to the open ones of "ball" projectiles. IF the jacket on a .264" "sporting" bullet is thin enough at the rear, and the propellant combustion has a reasonably high initial impulse, the bullet WILL "bump-up" a couple of thousandths of an inch. By the way, what is the availability of the six-round clips these days?.

I suspect this concept is a hangover from the days of the Minie Ball, with that bullet being a "racing fit" when it was rammed down the bore, but the skirt around the hollow base was expanded by the powder gases and engaged the rifling to provide sealing and spin, (and to scrape out some of the fouling from the previous shot). Patt-53 Enfields firing the PROPER hollow-based bullet were not exactly "scatterguns"; being able to lay down some impressive groups at several hundred yards..

If anyone plans to shoot a Carcano a LOT or have a whole room full of different models, Mr. Corbin may be worth contacting for the tools to make EXACTLY the bullet you want. NOT cheap toys but a definite solution and a whole new adventure!