A Model 1891 to keep my 1898 Krag, 1891 Mosin-Nagant and 1896 Swede company.

[RBruce]

Love those old long guns.

Information

Warning: This is a relatively older thread This discussion is older than 360 days. Some information contained in it may no longer be current.

[vintage hunter]

Nice find. Looks to be in above average condition for 116 years old. The early ones are hard to find in any condition, at least around here anyway.

[RBruce]

Just think, back in the early 1900s these four were on the same side!

[Aragorn243]

I've been watching for one of them for several years now with no luck. I wanted an Italian rifle and this one was the only one that didn't feel "toy" like to me. I handled one at a gun shop a few years ago and came close to buying it as the price was right but it was very badly corroded all along the barrel channel and I feared what I would find when I took it out of the stock.

[RBruce]

Is there a way to determine the actual diameter of the bore without having Cerrosafe or similar product?

[Patrick Chadwick]

Oil the clean bore liberally, and then whack a soft-lead .31 ball down it, like this:

Drop the ball in at the chamber and repeatedly drop a yard length of 1/4" brass rod onto it, giving the rod a downwards flick with your fingers to accelerate it. A brass rod cannot hurt the rifling, but provides a huge impulse to drive the ball down.

If the ball stays tight all the way the rifle is a prospect. Measure the ball and start thinking about possible bullets.

If the ball falls through the last couple of inches, the muzzle end is hopelessly worn and you can forget it.


Patrick

[RBruce]

Patrick, Since I don't have a .31" soft lead ball, I drove a .280 cast lead bullet into the muzzle. The measurements where the lead was displaced are .671mm and .696mm, lands and grooves. Can you determine the bore from these readings? If so, would standard 6.5mm bullets be likely to work in this rifle?

[Patrick Chadwick]

Since I don't have a .31" soft lead ball, I drove a .280 cast lead bullet into the muzzle.

That's fine, as long as you managed to get it right through the barrel! If you only drove it into the muzzle and out again, then you may be measuring a worn muzzle end, and do not know if the rest of the barrel is the same or tighter.The trouble with measuring the bore is that with a 3-groove bore you do not get a clean "Over grooves" figure, as there is a land opposite each groove. I hope your rifle has a 4-groove bore, in which case the max/min diameters on the slug do indeed correspond to the groove/land diameters.

Now for the worrying bit: The CIP bore/groove dimensions are given as 6.50 / 6.80 mm for a 4-groove barrel. You have measured 6.71 and 6.96. That sounds like a badly worn barrel. So please check your measuring devices (zero on micrometer or slide gauge, for instance).
As I wrote in my previous post, if the barrel is seriously bell-mouthed, there is not much you can do about it, and the rifle will probably shoot very poorly indeed.

If, on the other hand, the barrel is worn all the way down, i.e. oversized but constant, then the situation is not hopeless, but very awkward. You will need bullets that are thicker than the standard 0.264" (6.70 mm). If your measurements are correct, then a 6.5mm bullet will slide right into the muzzle. So try exactly that. If the 6.5 /.264 does indeed slide right in and stick somewhere down the bore, then the situation is hopeless. If it slides right through, then you have 2 options for shooting a) use the Hornady .268 (6.8mm) bullet made specifically for the Carcano - if you can still find them or b) use hard cast lead bullets with a diemeter of 6.9mm. The trouble with the first option is that there will be a lot of gas blow-by, and the trouble with the second option is that the neck of a loaded cartridge may be so enlarged that the cartridge will not chamber.

Check those measurements, and get hold of a piece of lead that you can drive right through the bore!


Patrick

[Patrick Chadwick]

Here in Mauserland one can get cast lead bullets in 0.270" and 0.272". Measure the neck diameter of a fired case. Measure the wall thickness.

Neck diameter - 2x wall thickness = inside neck diameter.

Why not measure the inside neck diameter directly? By all means do so, but the result is likely to be a trifle different. Smaller if you do not have the caliper jaws positioned perfectly on axis. Smaller because of the thickness of the jaws. But larger if you try to measure too tightly and force the case out of round. I find the first method more reliable.
Anyway:

Inside neck diameter - 2 thou (unless you have a bench-rest setup) - bullet tolerance (you will have to size all bullets for this kind of fine tuning) = the absolute maximum bullet diameter that you should try to chamber.

If the resulting bullet diameter is still too small for a good fit it the bore, then the absolute last chance is to use moderately hard bullets, and hope that they slug up enough to fit. But the softer the bullet the more rapidly you will get bore leading. There is no easy answer.


Patrick

[RBruce]

Looks like it is a worn barrel. I drove a .280 piece if soft lead into the chamber end and got 6.61 mm and 6.83 mm. The 6.5 bullets I have are 6.66, 6.67 and 6.8 in diameter.