How are sniper rifles made?

You first start with a rifle that is very accurate in factory trim. In the United States, one very popular rifle for conversion to a sniper rifle is the Remington Model 700, usually in caliber .308 Winchester - aka "7.62mm NATO." A rifle has three parts, the action, stock and barrel, and the only part you want from Remington is the action. You install the stock you are most comfortable with and a match-grade barrel - one that is very heavy. You then "glass bed" the stock - a process where you wrap the barrel in two layers of Teflon tape, fill the part of the stock under the barrel with a mix of slow-setting epoxy resin and chopped glass fiber, then bolt the action and barrel into the stock and let the plastic mixture form itself around the barrel. This cuts down on vibration in the barrel and makes the weapon more accurate. After adjusting and balancing the rifle, you attach a scope mount and a high-quality telescopic sight. Finally, you use match-grade ammo for the very highest accuracy.