No, the bullet will not seat.
how far does a 50 caliber sniper rifle shoot accuratly
No.
No.
You can from some, but they have to be designed to shoot both.
No
Although there are many variations, most AK47 shoot a ~30 caliber bullet (7.62mm).
100000000 meters
Yes
No, it won't fit. The .45 caliber bullet is 0.45" in diameter; the .30 caliber bullet is .15" smaller. The brass is different size too.
No. A smaller caliber will either not fire at all, or will split the cartridge casing if it does fire.
Generally speaking, no. You can only fire the caliber for which the gun is chambered. There are some exceptions, but not many.