This is a Gel Blaster adapter that I made for my kids' Gel Blasters. It allows you to use a soda bottle or similar to make a larger hopper. I use Propel favored water bottles. They are slim and make a nice size that is not too bulky, but holds about 2500-3000 gels. It works with both the rifle and the pistol gel blasters. Please note…there are a lot of different size threads used for soda and sport drinks. I used a PCO1810 thread standard. If folks want something specific, just leave me a comment.
Known compatible bottles my kids have used. ( I am sure there are more).
Funnel Design to help fill:
https://makerworld.com/en/models/490886#profileId-404367