And i have some question about this cannon.
the person who made this cannon say :This is my fifth pressurized air cannon (P.A.C. 5) that I have made and happens to be one of the most powerful cannon I have constructed yet. At a recent test, this cannon shot potatoes over twice as far as my P.A.C. 4. Latest shot: 1,276 meters with a specially made PVC dart.
Do you think that cannon can really shot 1276 meters ???
And on the picture, what is the utility of this part ?

and if you have any advice or impression on this cannon, said me
