Flow forming
Spinning and stretching the barrel under heat.
Flow forming takes a cast centre and spins the barrel while stretching it under heat and pressure. The barrel ends up thinner and denser than it would be cast.
The result sits between cast and forged: stronger and lighter than pure cast, cheaper than fully forged.
For a street build that never sees load or rock, flow formed is often the sensible commercial answer. We are clear about which process a part uses.