Rifling ends early and turns to a smooth bore

[terraformer]

I just bought a milsurp carcano where the rifling ends about 4 inches from the barrel end. Then it is smooth between there and the muzzle. Anyone ever hear of this? I found a patent for the technique online from 50 years after this rifle was made. The guy I bought it from (a NESr) has shot it and says it is fine. I believe that to be the case.

Is this aftermarket or original?

 

[vellnueve]

This is counterboring and is very common on surplus rifles. It was done after the rifle had been used and abused during the war during a rearsenal process.

 

[terraformer]

This is counterboring and is very common on surplus rifles. It was done after the rifle had been used and abused during the war during a rearsenal process.

Yup, that seems like what it is. Thanks.