In which conflict? Mercenaries have seen service throughout the world. In fact, mercenaries predate standing armies. Thus, a wide range of weaponry has been used by mercenaries.
By which side? The US and its allies used 7.62x51 for their sniper rifles. The North Vietnamese typically used 7.62x54R for theirs.
A sniper rifle is simply a rifle used by a military sniper. Just about every gun shop will carry hunting rifles. The type will vary depending on what you are hunting- squirrels, rabbit, deer, turkey, bear, elk or elephants. What you are calling a "sniper rifle" is simply a bolt action center fire rifle with a telescope.
Yes
You will have to define the term "Sniper rifle". It could mean anything. The only TRUE sniper rifle is a rifle issued to a sniper. They are simply rifles that are capable of long range accurate shooting. The rifles used by US military snipers during the Vietnam was were simply civilian hunting rifles with decent telescopes.
Mainly the US and it's allies, but all sides have used sniper rifles.
shotguns to handguns to sniper rifles etc...
This is subjected to opinion but they most used sniper rifles are the Barret 50. Cal and the Intervention. The Intervention is the more commonly used of the two so it is considered the best sniper rifle.
There are some accurised variants of the M16, SA80, and other 5.56 rifles out there which are designed and used as Designated Marksman rifles, but, in general, the 5.56x45 and .223 Remington cartridges really aren't the ideal choices for a sniper rifle.
A sniper rifle is a precision rifle that has a telescopic sight which allows operators to target an object that is far in the distance. Sniper rifles are used in military combat.
They used their modern sniper rifles and high-powered machine guns.
Yes, they were also used in ww1. they would just put a scope onto a standard rifle.
The effective range of a sniper rifle depends on factors like the type of rifle and ammunition used, as well as environmental conditions. Generally, modern sniper rifles have an effective range of around 800 to 1,500 meters. Some rifles can shoot even farther with specialized ammunition and skilled marksmanship.