Out of stock right now, they just came out and evidently have been popular.
https://www.teslong.com/Rifle-Borescope/WiFi-Rifle-Bore-ScopeI have the flexible one and it's plenty stiff for doing anything you need, no trouble turning it in the bore. I like it because it's longer than the rigid one so I don't have to swap from chamber to muzzle end to see the whole barrel.