Easier than buying one would be to convert a legal semi-auto to a “machine gun.”
Not so sure about bazookas.
Not as easy as you might think. Since about 1980 semi-autos have been designed to make it difficult to convert them.
The bet was a “Legal” gun, home conversion has been illegal since 1986.
Such “easy” conversions are DANGEROUS. They either force or risk runaway slamfires.
Such “easy” conversions are ILLEGAL. PERIOD. You’re looking at 10 years prison and $250,000 fine.
Whole lot easier, cheaper, and safer to buy an existing one thru proper BATFE channels. Figure about $5000, and a couple month’s paperwork processing & comprehensive background check.