Some useful info on Reddit covering our ATF Title II transfer rules for owning machine guns, suppressors and other items.
Looks to me like the information is accurate, but check your local listings to confirm.
The procedure at the link above outlines how individuals may comply with the National Firearm Act (NFA) of 1934 to own machine guns.
And why would individuals want to own machine guns?
Because they are fun.
And because we can.