What's the norm with airsoft shotgun barrel ID Are they still 6mm ID to give a burst fire effect or much bigger to give a spread as you would get with a shot gun Or even a stepped barrel

I'm not sure what airsoft usually does, but I feel as though a cluster of smaller 6mm barrels shrouded by a mock 12 gauge sized barrel would give you a decent spread while maintaining good velocities.

3x6mm barrels inside a large one.

Started to put something together, I made some 'shells' that will hold upto 8 airsoft BB's down the centre, it will also fire Nerf Rival balls.

Good job! You are already a specialist in this type of weapons. Well done. regards

Got it finished, not so powerful as an airsoft as it doesn't really have a barrel, only the length of the cartridge. Much more impressive as a Nerf gun, the grandson will love it

Might try and make a barrel insert to make the airsoft function better.

Made a push in barrel which is located by 2 screws, it's about 7mm ID so it gives small spread with 6 bb's I tried so far. Made 4 of the 'shells' which touch the end of the barrel when they are loaded.