Summary

This is a fusion of two awesome designs firstly

https://www.thingiverse.com/thing:1947646 awesome for the nice tight fitting locking ring and the aggressive rifling in the barrel

Secondly
https://www.thingiverse.com/thing:2216835 awesome for its interchangeable tips

Print Settings

Printer:

Anet A8

                                            <p class="detail-setting rafts"><strong>Rafts: </strong>                     <div><p>No</p></div></p>                                                                                <p class="detail-setting supports"><strong>Supports: </strong>                     <div><p>No</p></div></p>                                                                                <p class="detail-setting resolution"><strong>Resolution: </strong>                     <div><p>0.2mm</p></div></p>                                                                                <p class="detail-setting infill"><strong>Infill: </strong>                     <div><p>20%</p></div></p>

Post-Printing

As mentioned in the original file ( https://www.thingiverse.com/thing:1947646 ) there is an airgapped spacer to aid in the attachment printing which needs to be removed post printing this peice is about 12mm long and (if it does not fall out when you remove it from the bed) can be easily removed with a pair of long nosed pliers

007 Rifled Barrel For Nerf (With Safety Tip)