1000m
The M16 is an assault rifle that is a .223 caliber / 5.56 mm. like any weapon it is only as accurate as its shooter, <><><> It can be very accurate.
No You could build a rifle in .306" or any other caliber but you are likely referring to 30.06. A 30.06 rifle is referred to as "30 Caliber" but to be accurate it is nominally .308"
Provde the caliber.
In all likelhood, one of the bolt action pistols in a rifle caliber, such as 6mm. That holds the accuracy record for a rifle, and would likely do so for a pistol.
In excess of a mile.
200 yards
900 meters, depending on the rifle, sights, and skill of the user.
You would have to define what accurate means to you- but in general, Ruger makes good, accurate firearms.
Depends on the load and range.
Your rifle is a Marlin Model 81. Value could range from $50-$145, depending on condition. Most are around $100 or so. Accurate reliable hunting grade rifle.
More accurate than 90 percent of the people who will shoot it.
About 300 meters, depending on the rifle, sights, ammo, and skill of the shooter.