5.56x45mm NATO dummy round/snap-cap

thingiverse

This is a 5.56x45mm NATO cartridge designed according to the actual specifications for this round, but I may have inadvertently thickened the rim slightly so that it can be chambered and ejected without being ripped off - however, I created this design some time ago, so I'm unsure if that's actually the case. Sorry about any confusion. The bullet tip has been rounded off because pointed tips tend to print like a soft-serve ice cream cone; even so, I recommend printing the topmost layers slowly with the nozzle fan running at maximum speed if you're not doing this for the entire thing. If you want to use this as a snap cap, print it using 0.15 to 0.2mm layers with flexible filament and several walls or top/bottom layers along with near-solid infill. Make sure to print slower than usual and at higher-than-normal temperatures (with no nozzle fan if possible) so that all the layers fuse together really well - otherwise, the rim may get ripped off when you try to eject the round. Alternatively, you can print this in a rigid filament using multiple shells or walls (probably 5 or more), with zero percent infill and no bottom layer(s) to leave an open tube down the middle of the bullet for the firing pin to go into without hitting plastic.