Help nef sidekick

[Jpaw79]

I got my son a nef sidekick other day for 40 bucks nice gun but was not aware that it used the plastic cap holders wich are hard to locate lol please help if anyone has a 5/8 plug for nef that is direct primer style holler

 

[GM54-120]

Precision Rifle Bullet sells a bare primer breach plug for like $65.
https://www.prbullet.com/nef.htmhttps://www.prbullet.com/shop/products_view.php?sSKU=nef5.8