I read a piece in the comics recently on the Barakuda. The main issue as has been said before is consistency and also damage to the piston seal after relatively few shots. It is impossible to maintain this to anywhere near the standards required-and delivered-by modern air rifle designs. That I believe is why the system didn't take off and in particular wasn't extended to the HW80. This ignores the vital point about ammunition. Up to the transsonic velocity window(50 ft sec either side of the speed of sound so normally at sea level around 1050 to 1150 ft sec) the diabolo pellet design works best. It has stood the test of time and even now with FAC air rifles it is the serious choice for most of us in all calibres. OK I know that some shooters swear by the strangely shaped Defiants but I am not one of them. Above the speed of sound the bullet shape rules and that is why it is used in virtually all firearms.
The Barakuda remains a quirky piece of kit and as such has its place in a collection but I suspect not for regular use.
'It may be that your sole purpose in life is to serve as a warning to others'.