How far will it shoot and hit something??? i wouldn't put it past 300 - 400 yards comfortably
No, the 300 ultra mag cartidge is not interchangeable with the 300 win mag.
You can only shoot what is printed on the barrel. Mag and short mag are not the same.
yes
Which caliber?
About 150 yards.
a 150 grain bullet shoots 3290 fps
roughly about 22 miles accurate
what goes father a 300 short mag or a 300 mag
If your barrel is marked .300 Savage then you can shoot .300 Savage ammunition by any manufacturer. I do not know of a "300 Savage Winchester Magnum".
Around 300 yards.
Each weapon will prefer a different load. Only way to find out is to shoot as many different bullet weights as you can.