Well, that depends on the laws where you live. In most of the US, they're perfectly legal, with the one exception being California. In other countries, the laws are much different.
Depends on where you are.
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.
No
The bullet itself - no.
for a rifle it is thought to be a .50 calibre but a gun company made there own for there own sniper rifle the .408 calibre
You need to tell us which rifle. Chances are that there is some legal way to own it.
Only if you have the relevant BRITISH license. =]
It depends on what state you live in.
Yes
yes, I own one. they also make the model 14
no if he has a permit
Laws on this vary by country.