Back at the range yesterday with the Carcano. I put my giant sheet of cardboard at 25 yards to try to decipher POI. At 25 yards I am about 8" high. I failed to bring a rest, so I was shooting just arm-supported. With that being said and with my shakiness probably accounting for the large groups, I did shoot a selection of reloads. My 10gr (Unique) load was the best of the 3 loadings with a 2.4" 6-shot group. I think I will take the above advice and raise the front site to make my POA and POI the same. For those who have done this, do you just make it too tall then bring a small file to the range to adjust as you shoot?
Instead of raising your front sight, by gluing something to it, Numrich used to have different front sights available that could easily be fitted to the dovetail on your rifle. I don't know if they're still available.
It's almost a given that your rifle will shoot somewhere between 6-8 inches (12-16cm) high at 100 yards/meters for a 300 yard zero, with issued ammo.
There are tables on the internet and in some reloading manuals that give you "drop tables" for different bullet diameter/weights at different velocities at different ranges.
Most commercial targets have "one inch" lines, which can be difficult to see with the naked eye at 100 yds, but it's still easy to figure out an aiming point on the paper so that your point of impact is centered.
There are standardized targets on the internet, which are downloadable as well.
The white center X will be exactly six inches from the outside ring and eight inches from the bottom of the paper.
Using the bottom of the paper as an aiming point is easy and aligning it with the large black circle is easy as well.
Remember, the troops that qualified with those rifles had to do so from prone, off the elbows, prone and maybe resting on a sand bag, or whatever.