You need to be a bit more specific on which weapon.
five
About a year.
how long does it take to build a asimo
1 hour
how long did it take to build the half moon
how long did it take to build the scottish parliment?
how long did it take to build cabot tower
everything
hs2 will take 15 years to build
how long does it take to build a beam bridge of 2400 sq ft
4 years each
it took 3 years