Idea is to use an M16 bolt as a barrel -- highly accessible barrel with good op-sec. I was going to call it M16-22... but I just saw on Reddit there is a Beta exploring the same idea (Nutty Hoe by Black Lotus Coalition)... project is in better hands with Black Lotus

My approach: M16 bolt, drilled through using small guiding bushing and 5mm bit, ECM'd for boring, chamber, and rifling. Attached to Harlot v3 with a modified barrel block. Barrel is removable by unscrewing a cap on the muzzle end. Suppressor easily fitted thanks to the threads.

Lessons:

• 4.5mm bit might be better (more opportunity for boring to remove drill marks)
• jigs to drill from both sides more effective, gives a visual guide if the hole is straight
• rifling mandrel -- level of detail hard to achieve with 0.4 nozzle, 0.2 nozzle would be easier but becomes another BOM

Wonder if a HUGE bolt could hold the pressure of 9mm... the pipe is the most inaccessible component of 9mm builds???

-- SleepyEchidna