I suppose 'fake' was too inaccurate a description....but there are several reasons I used the term.
The barrel is made from water pipe which is likely 1/2" diameter....and is almost certainly 'seamed' .....and as such is likely to 'burst' on firing ....
The section of 'pipe' which the 'bolt' slides looks to be a section of half pipe (held by the nails ?) which looks decidedly fragile when you consider the force of the 'blow back' gasses from firing a bullet.
To aim....albeit inaccurately....would require 'sighting' down the barrel ....would you put your eyes anywhere near the bolt mechanism on this ?
I am not so certain that this has been fired....there are no scorch marks evident. I also find it hard to believe that the Mau Mau would risk serious injury or death just to fire one inaccurate round at the British
I think it would be better used to give the impression that you had a rifle than to fire this.
Perhaps, if shot gun cartridges ....with some of the 'charge' removed...were used this may have been 'more' functional
Regards David