Is this Scope broken ?

[dsa0510]

Has Anyone had experience with bugbuster 3-9x scope ?
i have this scope on my heavily modded 1377. 24 inch barrel steel breech metal barrel band hollow probe etc.. I always thought bad shot groups was fault of the gun, since this scope was a pretty descent and had a fine reputation.

this is what happened today:

I zero in my scope, it shoots one holer group for 3 pellets and 1 flyer downwards by 0.4 inch (from distance of 7.5 meters).
Next one shoots downwards 0.3 inch.
Next one shoots where I zeroed in.
Next one shoots downwards 0.5 inch
then all the pellets start shooting downwards at about 0.4-0.5 inch.
I locked the dials and scope rings and breech arent moving. This is only at 8 7.5 meters.

I had this scope and this modded 1377 for 3 months now. I always was a little suspicious of the scope because sometimes when I moved the dial around, and put it back to its same position, the POI would change. also, there were many cases where I would try to zero in the scope but POI wouldn't move even when I turn the dial. Like pellet shooting 0.5 inch above the cross hair, I turn dial downwards by 10 dials and it would still hit 0.5 inches above, So I turn it down another 10, same. turn another by 10, then all of a sudden pellet drops 1 inch below the cross hair. As if dial was stuck, then all 30 dials were moved at the sametime or something.
Sometimes the zero would stay well once I zero it in. But I always got no better than 0.6 inch group from 14meters at a perfect rest and 1lb trigger pull even with my best shooting pellet JSB match diabolo. I get at least 2 flyers in 8 shot group.

P.S I did not use up all the dials . There are many dials left for left/right up/down

I tried flipping scope rings

[BenjiHunter]

Try and clean the barrel.
As soon as my 1322 lose accuracy that's all I have to do.
But, 0.6 at 14 meters is large.It should do better.
I had a Bug buster on my 1322 at first. Then I put a big Barska scope on it
and my groups shrunk.
This is the Mac1 1322, 5 shots at 20 yards.

[dsa0510]

Try and clean the barrel.
As soon as my 1322 lose accuracy that's all I have to do.
But, 0.6 at 14 meters is large.It should do better.
I had a Bug buster on my 1322 at first. Then I put a big Barska scope on it
and my groups shrunk.
This is the Mac1 1322, 5 shots at 20 yards.

whoa @ that flyer.
I wish my gun could shoot like that...
I will definitely try cleaning the barrel. However this barrel is quite new. only ~200 pellets shot. Do you think cleaning will help ?

[BenjiHunter]

The flyer to the left is from another shooting session.
Yeah, try to clean it and see what happens.

[amb5500c]

At distances as close as you described, it takes quite a few clicks to notice a change in POI.
Richard