Apparently a trace "touch" by the 0.22 pellet or ball in the one inch long 0.246 dia. tunnel is sufficient to send the projectile into La-La-Land.
I opened the cylinders exit tunnel end (with partition et.al.), to 0.280 from 0.246. There was no significant drop or raise of impact with ball or pellet and close grouping of each type occured with the cylinder in full "Puff!" mode as opposed to "Bang!" or "Thump!".
I had thought a "graze" would leave a highly noticeable track in the tunnel.... apparently the momentary "touch" leaves little residue in the chamber passages.
So ETA had it figured out!.
Now I need a precision rod that fits a rifled bore like mine which can extend out past the cylinder without flex to guarantee centering (bore sight) of the add-on sonic device. This I will probably have to make in order to guarantee fit to my bore. -LarryS
Crack!,Bump!,Puff!... ETA appears correct.
Well thanks Larry.
However, saying touch is really not correct. The pellet is actually not touching anything other than air. What you are experiencing is really the drag from the shearing of air between very close object moving very fast past each other. The same principle how oil lubrication works in keeping parts from touching. If you keep the pellet far enough away from any surfaces, you won't get the effect.
Hope that explain things a bit.
However, saying touch is really not correct. The pellet is actually not touching anything other than air. What you are experiencing is really the drag from the shearing of air between very close object moving very fast past each other. The same principle how oil lubrication works in keeping parts from touching. If you keep the pellet far enough away from any surfaces, you won't get the effect.
Hope that explain things a bit.