Well, as described, no? You don't have to half-cock it to open...you just REALLY need to have it on half-cock when CLOSING, because otherwise you get an unexpected and VERY much unwanted loud BANG. Though that is noted as a potential malfunction of the gun.

> open it, manually remove the spent shell case

Or, as noted, just turn the gun over, something you can easily do one-handed while your other hand goes digging in pockets or holders for another shell.

>and put in
>a new one, close it, and then cock it fully. How tiresome does that
>get, either when target shooting or actually out hunting?

Can't speak for anyone else, but in my case? Not very. There aren't hordes of cacodemons bearing down at you when you're out with one of these. It's quite relaxing, at least to me, to do something slowly, methodically, and RIGHT.

...!
Gott's Leetle Feesh in Trousers!