Hm hm hm. Looks more like 26mm shotgun/mini warhead semi-auto. Handle connected right to barrel space which is a bit awkward but overwall everything in it's place. Except maybe optics mount is too high.
Neat design!! This reminds me of the french FAMAS assault rifle crossed with a grenade launcher. What exactly is a "nade rifle"? Is it just a name, or does it shoot nades (whatever those are?). Perhaps nade is slang for "grenade"? Perhaps secret grenade tech?