stupidly simple slap powered nerf gun. Not very accurate but... and here it is. the barrel can be added on to , or multiplied so you can turn it into a multi shot mortar like gun.. will be working on the multi barrel splitter next. the "cored" barrels that have the 5mm tube inside are designed to print standing up.. WITHOUT SUPPORTS!! as the supports will interfere with the threading. you may get some strings and such inside but the middle section is thick enough that it should fill in after a couple layers. Obviously this will depend on filament, printer, settings as well as environmental conditions... https://youtu.be/6MKXS6448Zc