ECM (v1) 30cm Rifling Mandrel-9x19

note that there is a V3 version out there... https://odysee.com/@c0ld\_d8rk\_h8nd:8

this design is taken from a: Rifling Mandrel-9x19-6gr-polygonal-1in9.82-Twist-8.82mm-Bore step file.
this for the use for a 300mm barrel and this can be printed in 1 piece. or in 2 pieces were you can use 2 pieces of 1.75mm filament to make a strong Rifling Mandrel

see the installation picture for more details

in case you like to have a even longer barrel then you could take a look at this remix that have been made of this concept https://cults3d.com/en/3d-model/tool/100mm-9x19mm-rifling-mandrel-extension