After finally getting my gun all set up for a nice, consistent shot string, I found that I can't get my gun zeroed. I think I have the gun all dialed in, I gas it up, and the point of impact changes. At first, I thought it was the scope, so I swapped them. Still have the same problem. Cleaned the barrel. Didn't help. Tried the recommended pellets and got some good groups that would suddenly shift or open up. The really odd thing is that the shifts seem to occur as the pressure changes. As I shoot and the pressure drops, the groups shift, but when I refill it, they shift back. Needless to say, this is very frustrating, and not at all conducive to accurate shooting. I am guessing that pressure shifts the barrel around, scattering my groups. Does anyone have any suggestions for fixing this? I just want my gun to work!
Thanks in advance,
Chris

1) The barrel screws are tight
2) The shroud is snug, and not smoked down
3) The shroud end cap o-ring is in place and snugged too
4) Signs of clipping
5) Feeding the pellets singley, to check the possibility that the mag is deforming the pellets when feeding

1. Checked barrel screws.
2. Hand tightened shroud - not sure what you mean by "smoked down".
3. End cap and Gaska shroud extension are tight.
4. No signs of clipping.
5. Haven't tried feeding pellets singly, but I have 2 clips, and the scattered groups are occurring from both.
I'm not so much worried about group size right now. It's giving signs that it can stack up ammo, but these little clusters of decent groups are constantly shifting. Two or three stack nice, then things drift. I had read in some forums about barrels shifting with changes in tube pressure, and this seems to be the case with me. I plan on going over every single bolt today to make sure they're tight, but all of the major ones (scope and breech) that are the usual offenders are snugged tight. What I'm hoping for is someone can tell me what I need to do to keep the pressure from affecting the barrel. I know that with some Discos this was a problem, and it was remedied by putting set screws in the barrel band to keep it from shifting. Unfortunately, this isn't really an option for the P-rod.
Thanks,
Chris

screws just a little. If they are too tight, the rotor inside will drag. Made a HUGE difference in my groups.

Have you had the barrel off? Could be a burr around the transfer port. Also, there is a way too
big step from the inlead to the lands and grooves. A piece of sandpaper on the end of a wooden
dowel in your hand drill will do wonders in this area. (smoother feeding of the pellet)









Head Gopher and Assistant
Match Director Ashland Air Rifle Range
Ashland OR

Regards,


Mark Gravelle